Bagaimana cara menggabungkan item yang hampir sama dengan SQL?

Jika Anda mencoba:

SET @name:='',@num:=0;

SELECT id,
       @num:= if(@name = user, @num, @num + 1) as number,
       @name := user as user
FROM foo
ORDER BY id ASC;

Ini memberikan:

+------+--------+------+
| id   | number | user |
+------+--------+------+
|    1 |      1 | a    |
|    2 |      1 | a    |
|    3 |      1 | a    |
|    4 |      2 | b    |
|    5 |      2 | b    |
|    6 |      2 | b    |
|    7 |      3 | a    |
|    8 |      3 | a    |
+------+--------+------+

Jadi Anda bisa mencoba:

SET @name:='',@num:=0;

SELECT COUNT(*) as count, user
FROM (
SELECT @num:= if(@name = user, @num, @num + 1) as number,
       @name := user as user
FROM foo
ORDER BY id ASC
) x
GROUP BY number;

Yang memberi

+-------+------+
| count | user |
+-------+------+
|     3 | a    |
|     3 | b    |
|     2 | a    |
+-------+------+

(Saya memanggil tabel saya foo dan juga hanya menggunakan nama a dan b karena saya terlalu malas untuk menulis zhangsan dan lisi berulang-ulang).