选择mysql命令 - 可能吗？

Question

这是我的表格设置:

mysql> describe a;
+-------+------------+------+-----+---------+----------------+
| Field | Type       | Null | Key | Default | Extra          |
+-------+------------+------+-----+---------+----------------+
| id    | int(11)    | NO   | PRI | NULL    | auto_increment | 
| x     | int(11)    | YES  |     | NULL    |                | 
| y     | varchar(1) | YES  |     | NULL    |                | 
+-------+------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> describe b;
+-------+------------+------+-----+---------+----------------+
| Field | Type       | Null | Key | Default | Extra          |
+-------+------------+------+-----+---------+----------------+
| id    | int(11)    | NO   | PRI | NULL    | auto_increment | 
| a     | int(11)    | NO   |     | NULL    |                | 
| z     | varchar(1) | YES  |     | NULL    |                | 
+-------+------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)

mysql> select * from a;
+----+------+------+
| id | x    | y    |
+----+------+------+
|  1 |    1 | a    | 
|  2 |    2 | b    | 
|  3 |    3 | c    | 
|  4 |    4 | d    | 
+----+------+------+
4 rows in set (0.01 sec)

mysql> select * from b;
+----+---+------+
| id | a | z    |
+----+---+------+
|  1 | 3 | q    | 
|  2 | 2 | a    | 
|  3 | 1 | u    | 
|  4 | 4 | x    | 
+----+---+------+
4 rows in set (0.01 sec)

这就是我想要做的事情:

mysql> select a.* from a, b where a.id = b.a order by b.z;
+----+------+------+
| id | x    | y    |
+----+------+------+
|  2 |    2 | b    | 
|  3 |    3 | c    | 
|  1 |    1 | a    | 
|  4 |    4 | d    | 
+----+------+------+
4 rows in set (0.00 sec)

但是,我想使用类似"SELECT*FROM ORDER BY(SELECT a FROM b ORDER BY z)"的语法.

这可能吗？

Answer 1

只要子查询返回1个结果,就可以按子查询进行排序,这意味着您需要在子查询中连接表.

我只是在我的应用程序中的查询生成器中设置它,这样的东西应该适合你:

SELECT a.*
FROM a,b
WHERE a.id = b.a
ORDER BY (
   SELECT z
   FROM b
   WHERE a.id = b.a
) ASC

Answer 2

我真的不认为你所描述的方式是可能的，我认为你需要加入表格。

查一下： http: //www.w3schools.com/Sql/sql_join_inner.asp