Tutorial SQL Server – Semua yang Anda Butuhkan Untuk Menguasai Transact-SQL

Di pasar saat ini, di mana sejumlah besar data dihasilkan setiap hari, sangat penting untuk memahami cara menangani data. SQL Server adalah lingkungan terintegrasi yang dikembangkan oleh Microsoft untuk menangani data. Dalam artikel tentang tutorial SQL Server ini, Anda akan mempelajari semua operasi dan perintah yang Anda perlukan untuk menjelajahi database Anda.

Untuk pemahaman Anda yang lebih baik, saya telah membagi blog ke dalam kategori berikut:

Selain perintah, topik berikut dibahas dalam artikel ini:

1. Apa itu SQL Server?
2. Instal SQL Server
3. Hubungkan ke SQL Server menggunakan SSMS
4. Akses Mesin Basis Data
5. Arsitektur SQL Server
6. Komentar dalam SQL
7. Tipe Data SQL Server
8. Kunci dalam database
9. Batasan dalam basis data
10. Operator
11. Fungsi Agregat
12. Fungsi Buatan Pengguna
13. Kueri Bertingkat
14. Bergabung
15. Pengulangan
16. Prosedur Tersimpan
17. Penanganan Pengecualian

***CATATAN*** Dalam Tutorial SQL Server ini, saya akan mempertimbangkan database di bawah ini sebagai contoh, untuk menunjukkan kepada Anda cara mempelajari dan menulis perintah.

Sebelum kita mulai memahami berbagai perintah yang digunakan di SQL Server, mari kita pahami apa itu SQL Server, arsitekturnya, dan cara menginstalnya.

Apa itu SQL Server?

Microsoft SQL Server adalah sistem manajemen basis data relasional. Ini mendukung bahasa Kueri Terstruktur dan dilengkapi dengan implementasi bahasa SQL-nya sendiri yang merupakan Transact-SQL(T-SQL) . Ini memiliki lingkungan terintegrasi untuk menangani database SQL, yaitu SQL Server Management Studio.

Komponen utama SQL Server adalah sebagai berikut:

• Mesin Database: Komponen ini menangani penyimpanan, Pemrosesan transaksi yang cepat, dan Pengamanan Data.
• SQL Server – Layanan ini digunakan untuk memulai, menghentikan, menjeda, dan melanjutkan instance MS SQL Server.
• Agen SQL Server – Layanan Agen Server memainkan peran penjadwal tugas dan dipicu oleh peristiwa apa pun atau sesuai kebutuhan.
• Browser SQL Server – Layanan ini digunakan untuk menghubungkan permintaan yang masuk ke instance SQL Server yang diinginkan.
• Pencarian Teks Lengkap SQL Server – Digunakan untuk memungkinkan pengguna menjalankan kueri teks lengkap terhadap data karakter dalam tabel SQL.
• Penulis VSS SQL Server – Memungkinkan pencadangan dan pemulihan file data saat SQL Server tidak berjalan.
• Layanan Analisis Server SQL (SSAS) – Layanan ini digunakan untuk menyediakan kemampuan analisis data, penambangan data, dan pembelajaran mesin. SQL Server juga terintegrasi dengan Python dan R untuk analisis data tingkat lanjut.
• Layanan Pelaporan SQL Server (SSRS) – Seperti namanya, layanan ini digunakan untuk menyediakan fitur dan kemampuan pengambilan keputusan termasuk integrasi dengan Hadoop.
• Layanan Integrasi SQL Server (SSIS) – Layanan ini digunakan untuk melakukan operasi ETL untuk berbagai jenis data dari berbagai sumber data.

Sekarang, setelah Anda mengetahui apa itu MS SQL Server, mari kita lanjutkan artikel ini tentang tutorial SQL Server dan memahami cara menginstal dan menyiapkan SQL Server.

Instal SQL Server

Ikuti langkah-langkah di bawah ini untuk menginstal SQL Server:

Langkah 1: Buka halaman resmi unduhan Microsoft SQL Server , di mana Anda akan menemukan opsi untuk menginstal SQL Server baik di tempat atau di awan.

Langkah 2: Sekarang, gulir ke bawah dan Anda akan melihat dua opsi: Edisi Pengembang &Perusahaan . Di sini, saya akan mengunduh edisi Pengembang . Untuk mengunduh, Anda hanya perlu mengeklik Unduh sekarang pilihan. Lihat di bawah.

Langkah 3: Setelah aplikasi diunduh, klik dua kali pada file dan Anda akan melihat jendela berikut.

Langkah 4: Sekarang, Anda dapat memilih salah satu dari 3 opsi untuk mengatur SQL Server. Di sini, saya hanya akan memilih opsi Dasar . Saat memilih opsi jenis instalasi, layar berikutnya adalah menerima perjanjian lisensi. Untuk melakukannya, klik Terima di jendela berikut.

Langkah 5: Selanjutnya, Anda harus menentukan lokasi instalasi SQL Server. Kemudian, Anda harus mengklik Instal.

Setelah Anda mengeklik Pasang , Anda akan melihat bahwa paket yang diperlukan sedang diunduh. Sekarang, setelah instalasi selesai, Anda akan melihat layar berikut:

Di sini, Anda dapat melanjutkan dan mengeklik Hubungkan Sekarang, atau Anda dapat Menyesuaikan instalasi. Untuk pemahaman Anda yang lebih baik, saya akan melanjutkan dan memilih Sesuaikan.

Langkah 6: Setelah Anda mengeklik Sesuaikan di jendela di atas, Anda akan melihat wizard berikut terbuka. di jendela berikut, klik Berikutnya.

Langkah 7 Setelah aturan dipasang secara otomatis, klik Berikutnya . Lihat di bawah.

Langkah 8: Selanjutnya, Anda harus memilih jenis instalasi. Jadi, pilih Lakukan penginstalan baru SQL Server 2017 pilihan dan kemudian klik Berikutnya.

Langkah 9: Di wizard yang terbuka, pilih edisi:Developer. Kemudian, klik Berikutnya . Lihat di bawah.

Langkah 10: Sekarang, baca dan terima perjanjian lisensi dengan check-in tombol radio lalu klik Berikutnya . Lihat di bawah.

Langkah 11 Dalam wizard di bawah ini Anda dapat memilih fitur yang ingin Anda instal. Juga, Anda dapat memilih direktori root instance dan kemudian klik Berikutnya . Di sini, saya akan memilih Layanan Mesin Basis Data .

Langkah 12: Selanjutnya Anda harus memberi nama instance, dan secara otomatis ID instance akan dibuat. Di sini, saya akan memberi nama instance "edureka". Kemudian, klik Berikutnya.

Langkah 13: Di wizard Konfigurasi Server, klik Berikutnya .

Langkah 14: Sekarang, Anda harus mengaktifkan mode otentikasi. Di sini, Anda akan melihat mode otentikasi Windows dan Mode Campuran . Saya akan memilih Mode Campuran. Kemudian, sebutkan kata sandinya dan saya akan menambahkan pengguna saat ini sebagai Admin dengan memilih Tambahkan Pengguna Saat Ini pilihan.

Langkah 15: Kemudian, pilih jalur file konfigurasi dan klik Instal .

Setelah instalasi selesai, Anda akan melihat layar berikut:

Hubungkan ke SQL Server menggunakan SSMS

Setelah SQL Server diinstal, langkah Anda selanjutnya adalah menghubungkan SQL Server ke SQL Server Management Studio. Untuk melakukannya ikuti langkah-langkah di bawah ini:

Langkah 1: Kembali, ke jendela berikut, dan klik instal SSMS pilihan.

Langkah 2: Setelah Anda mengklik opsi itu, Anda akan diarahkan ke halaman berikut, di mana Anda harus memilih Unduh SSMS.

Langkah 3: Setelah pengaturan diunduh, klik dua kali pada aplikasi dan Anda akan melihat wizard berikut terbuka.

Langkah 4: Klik Opsi penginstalan , di jendela di atas dan Anda akan melihat bahwa penginstalan akan dimulai.

Langkah 5: Setelah instalasi selesai Anda akan mendapatkan kotak dialog seperti yang ditunjukkan di bawah ini.

Setelah Anda menginstal SSMS, langkah selanjutnya adalah mengakses Database Engine .

Mengakses Mesin Basis Data

Saat Anda membuka studio manajemen server SQL dari menu mulai , sebuah jendela akan terbuka mirip dengan jendela yang ditunjukkan pada gambar di bawah ini.

Di sini, sebutkan Nama Server, Mode Otentikasi dan klik Hubungkan.

Setelah Anda mengeklik Hubungkan , Anda akan melihat layar berikut.

Baiklah teman-teman, begitulah cara Anda menginstal dan menyiapkan SQL Server. Sekarang, melangkah maju dalam tutorial SQL Server ini, mari kita pahami berbagai komponen arsitektur SQL Server.

Arsitektur SQL Server

Arsitektur SQL Server adalah sebagai berikut:

• Server Di sinilah layanan SQL diinstal dan database berada
• Mesin Relasional Berisi pengurai kueri, pengoptimal, dan pelaksana; dan eksekusi terjadi di mesin relasional.
• Pengurai Perintah Memeriksa sintaks kueri dan mengonversi kueri ke bahasa mesin.
• Pengoptimal Mempersiapkan rencana eksekusi sebagai output dengan mengambil statistik, kueri, dan pohon Aljabar sebagai input.
• Pelaksana Kueri Ini adalah tempat di mana kueri dijalankan selangkah demi selangkah
• Mesin Penyimpanan Ini bertanggung jawab untuk penyimpanan dan pengambilan data pada sistem penyimpanan, manipulasi data, pengelolaan dan penguncian transaksi.

Sekarang, setelah Anda mengetahui cara menyiapkan dan menginstal SQL Server dan berbagai komponennya, mari kita mulai menulis perintah di SQL Server. Tapi, sebelum itu izinkan saya membahas cara menulis komentar di SQL Server.

Komentar di SQL Server

Ada dua cara Anda dapat berkomentar dalam SQL, yaitu menggunakan s komentar satu baris atau m komentar akhir baris .

Komentar Satu Baris

Komentar satu baris dimulai dengan dua tanda hubung (–). Oleh karena itu, teks yang disebutkan setelah (–), hingga akhir satu baris akan diabaikan oleh kompilator.

Contoh:

--Example of single line comments

Komentar Multi-Baris

Komentar multi-baris dimulai dengan /* dan diakhiri dengan */ . Oleh karena itu, teks yang disebutkan di antara /* dan */ akan diabaikan oleh compiler.

Contoh:

/* Example for 
multi-line comments */

Sekarang di artikel tentang tutorial SQL Server ini, mari kita mulai dengan kumpulan perintah pertama yaitu perintah Bahasa Definisi Data.

Perintah Bahasa Definisi Data

Bagian artikel ini akan memberi Anda gambaran tentang perintah-perintah yang dapat digunakan untuk menentukan basis data Anda. Perintahnya adalah sebagai berikut:

• BUAT
• TURUN
• UBAH
• POTONGKAH
• GANTI NAMA

BUAT

Pernyataan ini digunakan untuk membuat tabel, database, atau tampilan.

Pernyataan 'CREATE DATABASE'

Pernyataan ini digunakan untuk membuat database.

Sintaks

CREATE DATABASE DatabaseName;

Contoh

CREATE DATABASE Students;

Pernyataan 'CREATE TABLE'

Seperti namanya, pernyataan ini digunakan untuk membuat tabel.

Sintaks

CREATE TABLE TableName (
Column1 datatype,
Column2 datatype,
Column3 datatype,
....

ColumnN datatype
);

Contoh

CREATE TABLE StudentInfo
(
StudentID int,
StudentName varchar(8000),
ParentName varchar(8000),
PhoneNumber int,
AddressofStudent varchar(8000),
City varchar(8000),
Country varchar(8000)
);

LEPASKAN

Pernyataan ini digunakan untuk menghapus tabel, database, atau tampilan yang sudah ada.

Pernyataan 'DROP DATABASE'

Pernyataan ini digunakan untuk menghapus database yang sudah ada. Informasi lengkap yang ada dalam database akan hilang segera setelah Anda menjalankan perintah di bawah ini.

Sintaks

DROP DATABASE DatabaseName;

Contoh

DROP DATABASE Students;

Pernyataan 'DROP TABLE'

Pernyataan ini digunakan untuk menghapus tabel yang sudah ada. Informasi lengkap yang ada di tabel akan hilang segera setelah Anda menjalankan perintah di bawah ini.

Sintaks

DROP TABLE TableName;

Contoh

DROP TABLE StudentInfo;

UBAH

Perintah ALTER digunakan untuk menambah, menghapus, atau mengubah kolom atau batasan dalam tabel yang ada.

Pernyataan 'ALTER TABLE'

Pernyataan ini digunakan untuk menambah, menghapus, mengubah kolom dalam tabel yang sudah ada sebelumnya.

Pernyataan 'ALTER TABLE' dengan ADD/DROP COLUMN

Pernyataan ALTER TABLE digunakan dengan perintah ADD/DROP Column untuk menambah dan menghapus kolom.

Sintaks

ALTER TABLE TableName
ADD ColumnName Datatype;

ALTER TABLE TableName
DROP COLUMN ColumnName;

Contoh

--ADD Column BloodGroup:
ALTER TABLE StudentInfo
ADD BloodGroup varchar(8000);
 
--DROP Column BloodGroup:
ALTER TABLE StudentInfo
DROP COLUMN BloodGroup ;

Pernyataan 'ALTER TABLE' dengan ALTER COLUMN

Pernyataan ALTER TABLE dapat digunakan dengan kolom ALTER untuk mengubah tipe data kolom yang ada dalam tabel.

Sintaks

ALTER TABLE TableName
ALTER COLUMN ColumnName Datatype;

Contoh

--Add a column DOB and change the data type from date to datetime.
ALTER TABLE StudentInfo
ADD DOB date;
ALTER TABLE StudentInfo
ALTER COLUMN DOB datetime;

POTONGKAT

Perintah SQL ini digunakan untuk menghapus informasi yang ada dalam tabel tetapi tidak menghapus tabel itu sendiri. Jadi, jika Anda ingin menghapus informasi yang ada di tabel, dan tidak menghapus tabel itu sendiri, Anda harus menggunakan perintah TRUNCATE. Jika tidak, gunakan perintah DROP.

Sintaks

TRUNCATE TABLE TableName;

Contoh

TRUNCATE TABLE StudentInfo;

GANTI NAMA

Pernyataan ini digunakan untuk mengganti nama satu atau beberapa tabel.

Sintaks

sp_rename 'OldTableName', 'NewTableName';

Contoh

sp_rename 'StudentInfo', 'Infostudents';

Berlanjut di artikel tutorial SQL Server ini, mari kita pahami berbagai tipe data yang didukung oleh SQL Server.

Tipe Data SQL Server

Selanjutnya, dalam artikel ini mari kita pahami berbagai jenis kunci dan batasan dalam database.

Berbagai Jenis Kunci Dalam Basis Data

Berikut ini adalah berbagai jenis kunci yang digunakan dalam database:

• Kunci Kandidat – Candidate Key adalah sekumpulan atribut yang dapat mengidentifikasi tabel secara unik. Sebuah tabel dapat memiliki lebih dari satu kunci kandidat, dan dari kunci kandidat yang dipilih, satu kunci dipilih sebagai Kunci Utama.
• Kunci Super – Himpunan atribut dapat secara unik mengidentifikasi sebuah tuple. Jadi, kunci kandidat, kunci unik, dan kunci utama adalah kunci super, tetapi sebaliknya.
• Kunci Utama – Kunci utama digunakan untuk mengidentifikasi setiap tupel secara unik.
• Kunci Alternatif – Kunci Alternatif adalah kunci kandidat yang tidak dipilih sebagai Kunci Utama.
• Kunci Unik – Kunci unik mirip dengan kunci utama, tetapi memungkinkan satu nilai NULL di kolom.
• Kunci Asing – Atribut yang hanya dapat mengambil nilai yang ada sebagai nilai dari beberapa atribut lain, adalah kunci asing untuk atribut yang dirujuk.
• Kunci Gabungan – Kunci komposit adalah kombinasi dari dua atau lebih kolom yang mengidentifikasi setiap tupel secara unik.

Kendala yang Digunakan Dalam Basis Data

Konstrain digunakan dalam database untuk menentukan aturan untuk data yang disimpan dalam tabel. Berbagai jenis batasan dalam SQL adalah sebagai berikut:

• BUKAN NULL
• UNIK
• PERIKSA
• DEFAULT
• INDEX

BUKAN NULL

Konstrain NOT NULL memastikan bahwa kolom tidak boleh memiliki nilai NULL.

Contoh

CREATE TABLE StudentsInfo
(
StudentID int NOT NULL,
StudentName varchar(8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000)
);

--NOT NULL on ALTER TABLE
ALTER TABLE StudentsInfo
ALTER COLUMN PhoneNumber int NOT NULL;

UNIK

Batasan ini memastikan bahwa semua nilai dalam kolom adalah unik.

Contoh

--UNIQUE on Create Table
 
CREATE TABLE StudentsInfo
(
StudentID int NOT NULL UNIQUE,
StudentName varchar(8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000)
);
 
--UNIQUE on Multiple Columns
 
CREATE TABLE StudentsInfo
(
StudentID int NOT NULL,
StudentName varchar(8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000)
CONSTRAINT UC_Student_Info UNIQUE(StudentID, PhoneNumber)
);
 
--UNIQUE on ALTER TABLE
 
ALTER TABLE StudentsInfo
ADD UNIQUE (StudentID);
 
--To drop a UNIQUE constraint
 
ALTER TABLE  StudentsInfo
DROP CONSTRAINT UC_Student_Info;

CHECK

The CHECK constraint ensures that all the values in a column satisfy a specific condition.

Example

--CHECK Constraint on CREATE TABLE
 
CREATE TABLE StudentsInfo
(
StudentID int NOT NULL,
StudentName varchar(8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000) CHECK (Country ='India')
);
 
--CHECK Constraint on multiple columns
 
CREATE TABLE StudentsInfo
(
StudentID int NOT NULL,
StudentName varchar8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000) CHECK (Country ='India'  AND City = 'Hyderabad')
);
 
--CHECK Constraint on ALTER TABLE
 
ALTER TABLE StudentsInfo
ADD CHECK (Country ='India');
 
--To give a name to the CHECK Constraint
 
ALTER TABLE StudentsInfo
ADD CONSTRAINT CheckConstraintName CHECK (Country ='India');
 
--To drop a CHECK Constraint
 
ALTER TABLE StudentsInfo
DROP CONSTRAINT CheckConstraintName;

DEFAULT

The DEFAULT constraint consists of a set of default values for a column when no value is specified.

Example

--DEFAULT Constraint on CREATE TABLE
 
CREATE TABLE StudentsInfo
(
StudentID int,
StudentName varchar(8000) NOT NULL,
ParentName varchar(8000),
PhoneNumber int ,
AddressofStudent varchar(8000) NOT NULL,
City varchar(8000),
Country varchar(8000) DEFAULT 'India'
);
 
--DEFAULT Constraint on ALTER TABLE
 
ALTER TABLE StudentsInfo
ADD CONSTRAINT defau_Country
DEFAULT 'India' FOR Country;
 
--To drop the Default Constraint
 
ALTER TABLE StudentsInfo
ALTER COLUMN Country DROP defau_Country;

INDEX

The INDEX constraint is used to create indexes in the table, through which you can create and retrieve data from the database very quickly.

Syntax

--Create an Index where duplicate values are allowed
CREATE INDEX IndexName
ON TableName (Column1, Column2, ...ColumnN);

--Create an Index where duplicate values are not allowed
CREATE UNIQUE INDEX IndexName
ON TableName (Column1, Column2, ...ColumnN);

Example

CREATE INDEX idex_StudentName
ON StudentsInfo (StudentName);
 
--To delete an index in a table
 DROP INDEX StudentsInfo.idex_StudentName;

Moving forward in this article on SQL Server tutorial, let us now understand the different Data Manipulation Language commands used in Microsoft SQL Server.

Data Manipulation Language commands

This section of the article will cover all those commands through which you can manipulate the database. The commands are as follows:

• USE
• INSERT INTO
• PERBARUI
• HAPUS
• MERGE
• PILIH
• CUBE
• ROLLUP
• OFFSET
• FETCH
• TOP
• PIVOT

Selain dari perintah ini, ada juga operator/fungsi manipulatif lainnya seperti:

• Operators
  • Operator Aritmatika
  • Assignment Operators
  • Bitwise Operators
  • Operator Perbandingan
  • Compound Operators
  • Operator Logika
  • Scope Resolution Operators
  • Set Operators
  • String Concatenation Operators
  • Fungsi Agregat
• User-Defined Functions

USE

This statement is used to select the database to start performing various operations on it.

Syntax

USE DatabaseName;

Example

USE Students;

INSERT INTO

The INSERT INTO statement is used to insert new records into an existing table.

Syntax

INSERT INTO TableName (Column1, Column2, Column3, ...,ColumnN)
VALUES (value1, value2, value3, ...);

--If you don't want to mention the column names then use the below syntax

INSERT INTO TableName
VALUES (Value1, Value2, Value3, ...);

Example

INSERT INTO StudentsInfo(StudentID, StudentName, ParentName, PhoneNumber, AddressofStudent, City, Country)
VALUES ('06', 'Sanjana','Kapoor', '9977331199', 'Buffalo Street House No 10', 'Kolkata', 'India');
 
INSERT INTO StudentsInfo
VALUES ('07', 'Vishal','Mishra', '9876509712', 'Nice Road 15', 'Pune', 'India');

PERBARUI

The UPDATE statement is used to modify or update the records already present in the table.

Syntax

UPDATE TableName
SET Column1 = Value1, Column2 = Value2, ...
WHERE Condition;

Example

UPDATE StudentsInfo
SET StudentName = 'Aahana', City= 'Ahmedabad'
WHERE StudentID = 1;

DELETE

The DELETE statement is used to delete the existing records in a table.

Syntax

DELETE FROM TableName WHERE Condition;

Example

DELETE FROM StudentsInfo
WHERE StudentName='Aahana';

MERGE

The MERGE statement is used to perform the INSERT, UPDATE and DELETE operations on a specific table, where the source table is provided. Lihat di bawah.

Syntax

MERGE TagretTableName USING SourceTableName
ON MergeCondition
WHEN MATCHED
THEN Update_Statement
WHEN NOT MATCHED
THEN Insert_Statement
WHEN NOT MATCHED BY SOURCE
THEN DELETE;

Example

To understand the MERGE statement, consider the following tables as the Source table and the Target table.

Source Table:

Target Table:

MERGE SampleTargetTable TARGET USING SampleSourceTable SOURCE ON (TARGET.StudentID = SOURCE.StudentID)                                                                                       
WHEN MATCHED AND TARGET.StudentName <> SOURCE.StudentName OR TARGET.Marks <> SOURCE.Marks 
THEN UPDATE SET TARGET.StudentName = SOURCE.StudentName, TARGET.Marks = SOURCE.Marks         
WHEN NOT MATCHED BY TARGET THEN  
INSERT (StudentID,StudentName,Marks) VALUES (SOURCE.StudentID,SOURCE.StudentName,SOURCE.Marks)
WHEN NOT MATCHED BY SOURCE THEN         
DELETE;    

Output

SELECT

The SELECT statement is used to select data from a database, table or view. The data returned is stored in a result table, called the result-set .

Syntax

SELECT Column1, Column2, ...ColumN
FROM TableName;

--(*) is used to select all from the table
SELECT * FROM table_name;

-- To select the number of records to return use:
SELECT TOP 3 * FROM TableName;

Example

-- To select few columns
SELECT StudentID, StudentName
FROM StudentsInfo;
 
--(*) is used to select all from the table
SELECT * FROM StudentsInfo;
 
-- To select the number of records to return use:
SELECT TOP 3 * FROM StudentsInfo;

We can also use the following keywords with the SELECT statement:

• BERBEDA
• PESAN OLEH
• GROUP MENURUT
• GROUPING SETS
• KALUSUS MEMILIKI
• INTO

DISTINCT

The DISTINCT keyword is used with the SELECT statement to return only different values.

Syntax

SELECT DISTINCT Column1, Column2, ...ColumnN
FROM TableName;

Example

SELECT DISTINCT PhoneNumber FROM StudentsInfo;

ORDER BY

This statement is used to sort the required results either in the ascending or descending order. By default, the results are stored in ascending order. Yet, if you wish to get the results in descending order, you have to use the DESC kata kunci.

Syntax

SELECT Column1, Column2, ...ColumnN
FROM TableName
ORDER BY Column1, Column2, ... ASC|DESC;

Example

-- Select all students from the 'StudentsInfo' table sorted by ParentName:
SELECT * FROM StudentsInfo
ORDER BY ParentName;
 
-- Select all students from the 'StudentsInfo' table sorted by ParentName in Descending order:
SELECT * FROM StudentsInfo
ORDER BY ParentName DESC;
 
-- Select all students from the 'StudentsInfo' table sorted by ParentName and StudentName:
SELECT * FROM StudentsInfo
ORDER BY ParentName, StudentName;

/* Select all students from the 'StudentsInfo' table sorted by ParentName 
in Descending order and StudentName in Ascending order: */
SELECT * FROM StudentsInfo
ORDER BY ParentName ASC, StudentName DESC;

GROUP BY

Pernyataan ini digunakan dengan fungsi agregat untuk mengelompokkan kumpulan hasil menurut satu atau beberapa kolom.

Syntax

SELECT Column1, Column2,..., ColumnN
FROM TableName
WHERE Condition
GROUP BY ColumnName(s)
ORDER BY ColumnName(s);

Example

-- To list the number of students from each city.
SELECT COUNT(StudentID), City
FROM StudentsInfo
GROUP BY City;

GROUPING SETS

GROUPING SETS were introduced in SQL Server 2008, used to generate a result-set that can be generated by a UNION ALL of the multiple simple GROUP BY clauses.

Syntax

SELECT ColumnNames(s)
FROM TableName
GROUP BY GROUPING SETS(ColumnName(s));

Example

SELECT StudentID, StudentName, COUNT(City)
from StudentsInfo
Group BY
GROUPING SETS
((StudentID, StudentName, City),(StudentID),(StudentName),(City));

HAVING

This clause is used in the scenario where the WHERE keyword cannot be used.

Syntax

SELECT ColumnName(s)
FROM TableName
WHERE Condition
GROUP BY ColumnName(s)
HAVING Condition
ORDER BY ColumnName(s);

Example

SELECT COUNT(StudentID), City
FROM StudentsInfo
GROUP BY City
HAVING COUNT(StudentID) > 2
ORDER BY COUNT(StudentID) DESC;

INTO

The INTO keyword can be used with the SELECT statement to copy data from one table to another. Well, you can understand these tables to be temporary tables. The temporary tables are generally used to perform manipulations on data present in the table, without disturbing the original table.

Syntax

SELECT *
INTO NewTable [IN ExternalDB]
FROM OldTable
WHERE Condition;

Example

-- To create a backup of table 'StudentsInfo'
SELECT * INTO StudentsBackup
FROM StudentsInfo;
 
--To select only few columns from StudentsInfo
SELECT StudentName, PhoneNumber INTO StudentsDetails
FROM StudentsInfo;
 
SELECT * INTO PuneStudents
FROM StudentsInfo
WHERE City = 'Pune';

CUBE

CUBE is an extension of the GROUP BY clause. It allows you to generate the sub-totals for all the combinations of the grouping columns specified in the GROUP BY clause.

Syntax

SELECT ColumnName(s)
FROM TableName
GROUP BY CUBE(ColumnName1, ColumnName2, ....., ColumnNameN);

Example

SELECT StudentID, COUNT(City)
FROM StudentsInfo
GROUP BY CUBE(StudentID)
ORDER BY StudentID;  

ROLLUP

ROLLUP is an extension of the GROUP BY clause. This allows you to include the extra rows which represent the subtotals. These are referred to as super-aggregated rows along with the grand total row.

Syntax

SELECT ColumnName(s)
FROM TableName
GROUP BY ROLLUP(ColumnName1, ColumnName2, ....., ColumnNameN);

Example

SELECT StudentID, COUNT(City)
FROM StudentsInfo
GROUP BY ROLLUP(StudentID);

OFFSET

The OFFSET clause is used with the SELECT and ORDER BY statement to retrieve a range of records. It must be used with the ORDER BY clause since it cannot be used on its own. Also, the range that you mention must be equal to or greater than 0. If you mention a negative value, then it shows an error.

Syntax

SELECT ColumnNames)
FROM TableName
WHERE Condition
ORDER BY ColumnName(s)
OFFSET RowsToSkip ROWS;

Example

Consider a new column Marks in the StudentsInfo tabel.

SELECT StudentName, ParentName
FROM StudentsInfo
ORDER BY Marks
OFFSET 1 ROWS;

FETCH

The FETCH clause is used to return a set of a number of rows. It has to be used in conjunction with the OFFSET clause.

Syntax

SELECT ColumnNames)
FROM TableName
WHERE Condition
ORDER BY ColumnName(s)
OFFSET RowsToSkip 
FETCH NEXT NumberOfRows ROWS ONLY;

Example

SELECT StudentName, ParentName
FROM StudentsInfo
ORDER BY Marks
OFFSET 1 ROWS
FETCH  NEXT 1 ROWS ONLY;

TOP

The TOP clause is used with the SELECT statement to mention the number of records to return.

Syntax

SELECT TOP Number ColumnName(s)
FROM TableName
WHERE Condition;

Example

SELECT TOP 3 * FROM StudentsInfo;

PIVOT

PIVOT is used to rotate the rows to column values and runs aggregations when required on the remaining column values.

Syntax

SELECT NonPivoted ColumnName,  
    [First Pivoted ColumnName] AS ColumnName,  
    [Second Pivoted ColumnName] AS ColumnName, 
    [Third Pivoted ColumnName] AS ColumnName,   
    ...  
    [Last Pivoted ColumnName] AS ColumnName  
FROM 
    (SELECT query which produces the data)   
    AS [alias for the initial query]  
PIVOT  
(  
    [AggregationFunction](ColumName)  
FOR  
[ColumnName of the column whose values will become column headers]   
    IN ( [First Pivoted ColumnName], [Second Pivoted ColumnName],  [Third Pivoted ColumnName]
    ... [last pivoted column])  
) AS [alias for the Pivot Table];

Example

To get a detailed example, you can refer to my article on SQL PIVOT and UNPIVOT. Next in this SQL Server Tutorial let us look into the different operators supported by Microsoft SQL Server.

Operators

The different types of operators supported by SQL Server are as follows:

• Operator Aritmatika
• Assignment Operators
• Bitwise Operators
• Operator Perbandingan
• Compound Operators
• Operator Logika
• Scope Resolution Operators
• Set Operators
• String Concatenation Operators

Let us discuss each one of them one by one.

Arithmetic Operators

Assignment Operators

Bitwise Operators

Comparison Operators

Compound Operators

Logical Operators

Scope Resolution Operators

Set Operators

Terutama ada tiga set operasi:UNION, INTERSECT, MINUS. Anda dapat merujuk ke gambar di bawah ini untuk memahami operasi yang ditetapkan dalam SQL. Refer to the below image:

String Operators

Aggregate Functions

The different aggregate functions supported by SQL Server are as follows:

User-Defined Functions

Microsoft SQL Server allows the users to create user-defined functions which are routines. These routines accept parameters, can perform simple to complex actions and return the result of that particular action as a value. Here, the value returned can either be a single scalar value or a complete result-set.

You can use user-defined functions to:

• Allow modular programming
• Reduce network traffic
• Allow faster execution of queries

Also, there are different types of user-defined functions you can create. Mereka adalah:

• Scalar Functions: Used to return a single data value of the type defined in the RETURNS clause.
• Table-Valued Functions: Used to return a table data type.
• System Functions: A variety of system functions are provided by the SQL Server to perform different operations.

Well, apart from the user-defined functions, there is a bunch of in-built functions in SQL Server; which can be used to perform a variety of tasks. Moving on in this article on SQL Server tutorial, let us now understand what are nested queries.

Nested Queries

Nested queries are those queries that have an outer query and inner subquery. So, basically, the subquery is a query which is nested within another query such as SELECT, INSERT, UPDATE or DELETE. Refer to the image below:

Next in this SQL Server tutorial, let us understand the different types of joins in SQL.

Joins

Joins are used to combine tuples from two or more tables, based on a related column between the tables. There are four types of joins:

• INNER JOIN: Returns records that have matching values in both the tables.
• LEFT JOIN: Returns records from the left table, and also those records which satisfy the condition from the right table.
• RIGHT JOIN: Returns records from the right table, and also those records which satisfy the condition from the left table.
• FULL JOIN: Returns records which either have a match in the left or the right table.

Consider the following table along with the StudentsInfo table, to understand the syntax of joins.

INNER JOIN

Syntax

SELECT ColumnName(s)
FROM Table1
INNER JOIN Table2 ON Table1.ColumnName = Table2.ColumnName;

Example

SELECT Subjects.SubjectID, StudentsInfo.StudentName
FROM Subjects
INNER JOIN StudentsInfo ON Subjects.StudentID = StudentsInfo.StudentID;

LEFT JOIN

Syntax

SELECT ColumnName(s)
FROM Table1
LEFT JOIN Table2 ON Table1.ColumnName = Table2.ColumnName;

Example

SELECT StudentsInfo.StudentName, Subjects.SubjectID
FROM StudentsInfo
LEFT JOIN Subjects ON StudentsInfo.SubjectID = Subjects.SubjectID
ORDER BY StudentsInfo.StudentName;

RIGHT JOIN

Syntax

SELECT ColumnName(s)
FROM Table1
RIGHT JOIN Table2 ON Table1.ColumnName = Table2.ColumnName;

Example

SELECT StudentsInfo.StudentName, Subjects.SubjectID
FROM StudentsInfo
RIGHT JOIN Subjects ON StudentsInfo.SubjectID = Subjects.SubjectID
ORDER BY StudentsInfo.StudentName;

FULL JOIN

Syntax

SELECT ColumnName(s)
FROM Table1
FULL OUTER JOIN Table2 ON Table1.ColumnName = Table2.ColumnName;

Example

SELECT StudentsInfo.StudentName, Subjects.SubjectID
FROM StudentsInfo
FULL OUTER JOIN Subjects ON StudentsInfo.SubjectID = Subjects.SubjectID
ORDER BY StudentsInfo.StudentName;

Next, in this article on SQL Server tutorial, let us understand the different types of loops supported by the SQL Server.

Loops

The different control-of-flow commands are as follows:

• BEGIN..END
• BREAK
• CONTINUE
• GOTO
• IF..ELSE
• RETURN
• WAITFOR
• WHILE

Let us discuss each one of them one by one.

BEGIN..END

These keywords are used to enclose a series of SQL statements. Then, this group of SQL statements can be executed.

Syntax

BEGIN   
     { SQLStatement | StatementBlock }   
END

BREAK

This statement is used to exit the current WHILE loop. In case, the current WHILE loop is nested inside another loop, then the BREAK statement exits only the current loop and the control is passed on to the next statement in the current loop. The BREAK statement is generally used inside an IF statement.

Syntax

BREAK;

CONTINUE

The CONTINUE statement is used to restart a WHILE loop. So, any statements after the CONTINUE keyword will be ignored.

Syntax

CONTINUE;

Here, Label is the point after which processing starts if a GOTO is targeted to that particular label.

GOTO

Used to alter the flow of execution to a label. The statements written after the GOTO keyword are skipped and processing continues at the label.

Syntax

Define Label:   
Label:   
Alter Execution:  
GOTO Label

Here, Label is the point after which processing starts if a GOTO is targeted to that particular label.

IF..ELSE

Like any other programming language, the If-else statement in SQL Server tests the condition and if the condition is false then ‘else’ statement is executed.

Syntax

IF BooleanExpression      
     { SQLStatement | StatementBlock }   
[ ELSE   
     { SQLStatement | StatementBlock } ]

RETURN

Used to exit unconditionally from a query or procedure. So, the statements which are written after the RETURN clause are not executed.

Syntax

RETURN [ IntegerExpression ]

Here, an integer value is returned.

WAITFOR

The WAITFOR control flow is used to block the execution of a stored procedure, transaction or a batch until a specific statement modifies, returns at least one row or a specified time or time interval elapses.

Syntax

WAITFOR   
{  
    DELAY 'TimeToPass'   
  | TIME 'TimeToExecute'   
  | [ ( RecieveStatement ) | ( GetConversionGroupStatement ) ]   
    [ , TIMEOUT timeout ]  
}

where,

• DELAY – Period of time that must pass
• TimeToPass – Period of time to wait
• TIME – The time when the stored procedure, transaction or the batch runs.
• TimeToExecute – The time at which the WAITFOR statement finishes.
• RecieveStatement – A valid RECEIVE statement.
• GetConversionGroupStatement – A valid GET CONVERSATION GROUP statement.
• TIMEOUT timeout – Specifies the period of time, in milliseconds, to wait for a message to arrive on the queue.

WHILE

This loop is used to set a condition for repeated execution of a particular SQL statement or a SQL statement block. The statements are executed as long as the condition mentioned by the user is TRUE. As soon as the condition fails, the loop stops executing.

Syntax

WHILE BooleanExpression 
{ SQLStatement | StatementBlock | BREAK | CONTINUE }

Now, that you guys know the DML commands, let’s move onto our next section in this article on SQL Tutorial i.e. the DCL commands.

Data Control Language Commands (DCL)

This section of SQL Server tutorial will give you an idea about the command through which are used to enforce database security in multiple user database environments. The commands are as follows:

• GRANT
• REVOKE

GRANT

The GRANT command is used to provide access or privileges on the database and its objects to the users.

Syntax

GRANT PrivilegeName
ON ObjectName
TO {UserName |PUBLIC |RoleName}
[WITH GRANT OPTION];

where,

• PrivilegeName – Is the privilege/right/access granted to the user.
• ObjectName – Name of a database object like TABLE/VIEW/STORED PROC.
• UserName – Name of the user who is given the access/rights/privileges.
• PUBLIC – To grant access rights to all users.
• RoleName – The name of a set of privileges grouped together.
• WITH GRANT OPTION – To give the user access to grant other users with rights.

Example

-- To grant SELECT permission to StudentsInfo table to user1
GRANT SELECT ON StudentsInfo TO user1;

REVOKE

The REVOKE command is used to withdraw the user’s access privileges given by using the GRANT command.

Syntax

REVOKE PrivilegeName 
ON ObjectName 
FROM {UserName |PUBLIC |RoleName}

Example

-- To revoke the granted permission from user1
REVOKE SELECT ON StudentsInfo TO user1;

Moving on in this SQL Server tutorial, let us understand the how to create and use Stored Procedures.

Stored Procedures

Stored Procedures are reusable units that encapsulate a specific business logic of the application. So, it is a group of SQL statements and logic, compiled and stored together to perform a specific task.

Syntax

CREATE [ OR REPLACE] PROCEDURE procedure_name [
(parameter_name [IN | OUT | IN OUT] type [ ])]
{IS | AS }
BEGIN [declaration_section]
executable_section 
//SQL statement used in the stored procedure
END
GO

Example

--Create a procedure that will return a student name when the StudentId is given as the input parameter to the stored procedure
Create  PROCEDURE GetStudentName 
(
@StudentId INT, --Input parameter ,  
@StudName VARCHAR(50)  OUT  --Output parameter, 
AS
BEGIN
SELECT @StudName = StudentName FROM StudentsInfo WHERE StudentID=@StudentId
END

Steps to execute:

• • • Declare @StudName as nvarchar(50)
    • EXEC GetStudentName 01, @StudName output
    • SELECT @StudName

The above procedure returns the name of a particular student, on giving that students id as input. Next in this SQL Server tutorial, let us understand the transaction control language commands.

Transaction Control Language Commands (TCL)

This section of SQL Server tutorial will give you an insight into the commands which are used to manage transactions in the database. The commands are as follows:

• COMMIT
• ROLLBACK
• SAVEPOINT

COMMIT

The COMMIT command is used to save the transaction into the database.

Syntax

COMMIT;

ROLLBACK

The ROLLBACK command is used to restore the database to the last committed state.

Syntax

ROLLBACK;

NOTE: When you use ROLLBACK with SAVEPOINT, then you can directly jump to a savepoint in an ongoing transaction. Syntax:ROLLBACK TO SavepointName;

SAVEPOINT

The SAVEPOINT command is used to temporarily save a transaction. So if you wish to rollback to any point, then you can save that point as a ‘SAVEPOINT’.

Syntax

SAVEPOINT SAVEPOINTNAME;

Consider the below table to understand the working of transactions in the database.

Now, use the below SQL queries to understand the transactions in the database.

INSERT INTO StudentTable VALUES(5, 'Avinash');
COMMIT;
UPDATE StudentTable SET name = 'Akash' WHERE id = '5';
SAVEPOINT S1;
INSERT INTO StudentTable VALUES(6, 'Sanjana');
SAVEPOINT S2;
INSERT INTO StudentTable VALUES(7, 'Sanjay');
SAVEPOINT S3;
INSERT INTO StudentTable VALUES(8, 'Veena');
SAVEPOINT S4;
SELECT * FROM StudentTable;

Next in this article on SQL Server tutorial let us understand how to handle exceptions in Transact-SQL.

Exception Handling

There are two types of exceptions, i.e, the system-defined exceptions and the user-defined exceptions. As the name suggests, exception handling is a process through which a user can handle the exceptions generated. To handle exceptions you have to understand the following control flow statements:

• THROW
• TRY…CATCH

THROW

This clause is used to raise an exception and transfers the execution to a CATCH block of a TRY…CATCH construct.

Syntax

THROW [ { ErrorNumber | @localvariable },  
        { Message | @localvariable },  
        { State | @localvariable } ]   
[ ; ]

where,

• ErrorNumber – A constant or variable that represents the exception.
• Message – A variable or string that describes the exception.
• State – A constant or variable between 0 and 255 that indicates the state to associate with the message.

THROW 51000, 'Record does not exist.', 1;  

TRY..CATCH

Used to implement exception handling in Transact-SQL. A group of statements can be enclosed in the TRY block. In case an error occurs in the TRY block, control is passed to another group of statements that are enclosed in a CATCH block.

Syntax

BEGIN TRY  
     { SQLStatement | StatementBlock}  
END TRY  
BEGIN CATCH  
     [ { SQLStatement | StatementBlock } ]  
END CATCH  
[ ; ]

BEGIN TRY  
    SELECT * FROM StudentsInfo;  
END TRY  
BEGIN CATCH  
    SELECT   
        ERROR_NUMBER() AS ErNum , ERROR_MESSAGE() AS ErMsg;  
END CATCH

W ith this, we come to the end of this article on SQL Server Tutorial. I hope you enjoyed reading this article on SQL Server Tutorial For Beginners. I f you wish to get a structured training on MySQL, then check out our MySQL DBA Certification Training yang dilengkapi dengan pelatihan langsung yang dipimpin instruktur dan pengalaman proyek kehidupan nyata. This training will help you understand MySQL in-depth and help you achieve mastery over the subject. Ada pertanyaan untuk kami? Please mention it in the comments section of ”SQL Server Tutorial ” dan saya akan menghubungi Anda kembali.