tryso

如果table1的某一行的a 与table2的c对应，就删除table1的这一行。

table1
a   | b
－－－－－
1   | 100
2   | 200

table2
c   |
－－－－
1   |

在SQL server 里面可以这样写到：
delete table1 from table1 a join table2 b on a.a=b.c;

但在MySQL里面就不行，应该怎么改？谢谢！

涩兔子

[code:1]
DELETE
    FROM table1 t1 LEFT JOIN table2 t2 ON t1.a = t2.c
    WHERE t1.a = xxx
[/code:1]

tryso

出现问题:

mysql> DELETE
    ->     FROM table1 t1 LEFT JOIN table2 t2 ON t1.a = t2.c ;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use near 'LEFT
JOIN table2 t2 ON t1.a = t2.c' at line 2
mysql>

涩兔子

http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fbugs.mysql.com%2Fbug.php%3Fid%3D2171&ei=MmFIRIDkOoiUogLut_2iBQ&sig2=mgf7pnaBw7jTXvnxh9Abcw
MySQL居然不支持连接删除
http://dev.mysql.com/doc/refman/5.0/en/delete.html
DELETE t1, t2 FROM t1, t2, t3 WHERE t1.id=t2.id AND t2.id=t3.id;

Or:

DELETE FROM t1, t2 USING t1, t2, t3 WHERE t1.id=t2.id AND t2.id=t3.id;

推荐使用PostgreSQL了

tryso

网上有这样回复，不知道运行效率怎样？

delete from t1 where t1.a in (select t2.c from t2);

虚拟主机一般只支持 MySQL或 SQL Server。无奈～

jiangtao9999

MySQL 不支持查询嵌套，所以 SQL 语句要构思严谨……………

好像 5 支持嵌套了？

玛宁

MySQL用InnoDB做Table的Engine的话就持连接删除了