MySQLでLIMITを使用した複数のWHERE？

このために、UNIONALL演算子を使用できます。まずテーブルを作成しましょう-

mysql> create table DemoTable
   -> (
   -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> Subject varchar(100)
   -> );
Query OK, 0 rows affected (0.64 sec)

挿入コマンド-

mysql> insert into DemoTable(Subject) values('MySQL');
Query OK, 1 row affected (0.13 sec)

mysql> insert into DemoTable(Subject) values('MySQL');
Query OK, 1 row affected (0.19 sec)

mysql> insert into DemoTable(Subject) values('MongoDB');
Query OK, 1 row affected (0.14 sec)

mysql> insert into DemoTable(Subject) values('MongoDB');
Query OK, 1 row affected (0.13 sec)

mysql> insert into DemoTable(Subject) values('MySQL');
Query OK, 1 row affected (0.27 sec)

mysql> insert into DemoTable(Subject) values('Java');
Query OK, 1 row affected (0.25 sec)

mysql> insert into DemoTable(Subject) values('MySQL');
Query OK, 1 row affected (0.11 sec)

mysql> insert into DemoTable(Subject) values('MongoDB');
Query OK, 1 row affected (0.14 sec)

selectステートメントを使用してテーブルのすべてのレコードを表示する-

mysql> select *from DemoTable;

出力

+----+---------+
| Id | Subject |
+----+---------+
| 1  | MySQL   |
| 2  | MySQL   |
| 3  | MongoDB |
| 4  | MongoDB |
| 5  | MySQL   |
| 6  | Java    |
| 7  | MySQL   |
| 8  | MongoDB |
+----+---------+
8 rows in set (0.00 sec)

以下は、MySQLでLIMITを使用して複数のWHEREを実装するためのクエリです-

mysql> (select *from DemoTable where Subject='MySQL' limit 3)
   -> union all
   -> (select *from DemoTable where Subject='MongoDB' limit 5)
   -> ;

出力

+----+---------+
| Id | Subject |
+----+---------+
| 1  | MySQL   |
| 2  | MySQL   |
| 5  | MySQL   |
| 3  | MongoDB |
| 4  | MongoDB |
| 8  | MongoDB |
+----+---------+
6 rows in set (0.00 sec)