草薙です。

>レコードの中身が複数、つまり
>dress_type = '5,7'
>と言うことです。

そのような設計の場合、神野様が [mysql 07923] で仰っているとおり、WHERE 
IN (1, 3, 5) で抽出されないことは自明であるかと思います。

個人的にはdress_type を int 型として、下記のようなテーブル連結を行った方
が、後々の扱いがスマートになるような気がします。

mysql> create table tbdress (num int, dress_name varchar(10));
Query OK, 0 rows affected (0.00 sec)

mysql> create table tbdress_a ( num int, dress_type int );
Query OK, 0 rows affected (0.00 sec)

mysql> insert into tbdress values(1, 'dress A');
Query OK, 1 row affected (0.00 sec)

mysql> insert into tbdress values(2, 'dress B');
Query OK, 1 row affected (0.00 sec)

mysql> insert into tbdress_a values(1, 5 );
Query OK, 1 row affected (0.00 sec)

mysql> insert into tbdress_a values( 1, 7 );
Query OK, 1 row affected (0.00 sec)

mysql> insert into tbdress_a values( 2, 3 );
Query OK, 1 row affected (0.00 sec)

mysql> insert into tbdress_a values( 2, 4 );
Query OK, 1 row affected (0.00 sec)

mysql> select * from tbdress;
+------+------------+
| num  | dress_name |
+------+------------+
|    1 | dress A    |
|    2 | dress B    |
+------+------------+
2 rows in set (0.00 sec)

mysql> select * from tbdress_a;
+------+------------+
| num  | dress_type |
+------+------------+
|    1 |          5 |
|    1 |          7 |
|    2 |          3 |
|    2 |          4 |
+------+------------+
4 rows in set (0.00 sec)

mysql> select t1.num, t1.dress_name, t2.dress_type from tbdress t1 inner join tb
dress_a t2 on t1.num=t2.num;
+------+------------+------------+
| num  | dress_name | dress_type |
+------+------------+------------+
|    1 | dress A    |          5 |
|    1 | dress A    |          7 |
|    2 | dress B    |          3 |
|    2 | dress B    |          4 |
+------+------------+------------+
4 rows in set (0.00 sec)

mysql> select t1.num, t1.dress_name, t2.dress_type from tbdress t1 inner join tb
dress_a t2 on t1.num=t2.num where t2.dress_type in ( 1,3,5 );
+------+------------+------------+
| num  | dress_name | dress_type |
+------+------------+------------+
|    1 | dress A    |          5 |
|    2 | dress B    |          3 |
+------+------------+------------+
2 rows in set (0.00 sec)



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草薙考司 <kusanagi@xxxxxxxxxx>