kembalikan baris kosong untuk data yang tidak ada

Anda dapat melakukan sesuatu seperti di bawah ini:

# table creation:

drop table if exists test_table;

create table test_table (your_date date, your_value int(11));
insert into test_table (your_date, your_value) values ('2020-01-01', 1);
insert into test_table (your_date, your_value) values ('2020-01-01', 2);
insert into test_table (your_date, your_value) values ('2020-01-03', 2);
insert into test_table (your_date, your_value) values ('2020-01-07', 3);
insert into test_table (your_date, your_value) values ('2020-01-08', 4);
insert into test_table (your_date, your_value) values ('2020-01-08', 1);

Ini membuat daftar pada dasarnya semua tanggal. Anda kemudian memfilter tanggal yang Anda minati, bergabung dengan meja dan grup Anda.

Anda juga dapat mengganti tanggal dalam pernyataan where dengan subqueries (tanggal minimum dan maksimum tabel Anda) untuk membuatnya dinamis

Ini sedikit solusi tetapi berhasil.

select sbqry.base_date, sum(ifnull(t.your_value, 0))
from (select adddate('1970-01-01',t4.i*10000 + t3.i*1000 + t2.i*100 + t1.i*10 + t0.i) base_date from
    (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t0,
    (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t1,
    (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t2,
    (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t3,
    (select 0 i union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) t4) sbqry
left join test_table t on base_date = t.your_date
where sbqry.base_date between '2020-01-01' and '2020-01-08'
group by sbqry.base_date;

masukan:

+------------+------------+
| your_date  | your_value |
+------------+------------+
| 2020-01-01 |          1 |
| 2020-01-01 |          2 |
| 2020-01-03 |          2 |
| 2020-01-07 |          3 |
| 2020-01-08 |          4 |
| 2020-01-08 |          1 |
+------------+------------+

keluaran:

+------------+------------------------------+
| base_date  | sum(ifnull(t.your_value, 0)) |
+------------+------------------------------+
| 2020-01-01 |                            3 |
| 2020-01-02 |                            0 |
| 2020-01-03 |                            2 |
| 2020-01-04 |                            0 |
| 2020-01-05 |                            0 |
| 2020-01-06 |                            0 |
| 2020-01-07 |                            3 |
| 2020-01-08 |                            5 |
+------------+------------------------------+