mysql 子查询 having为空问题 a:SELECT * FROM `qq` WHERE qq not in(SELECT qqFROM qq_logHAVING count( qq ) <3)b: SELECT qq FROM qq_log HAVING count( qq ) <3当b没有记录的时候,a也没记录,如何解决这个问题? 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 当b没有记录时,a变成了SELECT * FROM `qq` WHERE qq not in(null);这样肯定没记录了,除非 qq包含NULL值。 mysql> select ID ,date from Table_S;+----+---------------------+| ID | date |+----+---------------------+| 1 | 2011-10-24 00:00:00 || 2 | 2011-10-25 00:00:00 || 3 | 2011-10-26 00:00:00 || 4 | 2011-10-27 00:00:00 || 5 | 2011-10-28 00:00:00 || 6 | 2011-10-29 00:00:00 || 7 | 2011-10-30 00:00:00 || 8 | 2011-10-31 00:00:00 |+----+---------------------+8 rows in set (0.00 sec)mysql> select ID ,date from Table_S having count(ID)<3;Empty set (0.00 sec)mysql> select ID ,date from Table_S where ID not in(select ID from Table_S having count(ID)<3);+----+---------------------+| ID | date |+----+---------------------+| 1 | 2011-10-24 00:00:00 || 2 | 2011-10-25 00:00:00 || 3 | 2011-10-26 00:00:00 || 4 | 2011-10-27 00:00:00 || 5 | 2011-10-28 00:00:00 || 6 | 2011-10-29 00:00:00 || 7 | 2011-10-30 00:00:00 || 8 | 2011-10-31 00:00:00 |+----+---------------------+8 rows in set (0.00 sec) mysql 支持 两台服务器的链表查下吗 有关索引的问题 msql奇怪问题! 外键就是引用自己的主键,如何删除表中数据 关于 MYSQL_SET_CHARSET_NAME Weblogic 7.0 替换mysql驱动包 求PL/pgSQL问题答案 MYSQL中无法导入的字该怎么办?比如下面的 恳求大家前来讨论MySQL的优缺点,这里是我这几天的心得,希望得到大家点评.(总120分,内有链接) 求一条数据库查询语句 新手学习MYSQL的步骤 sql查询 同一个字段 同时满足多个条件
+----+---------------------+
| ID | date |
+----+---------------------+
| 1 | 2011-10-24 00:00:00 |
| 2 | 2011-10-25 00:00:00 |
| 3 | 2011-10-26 00:00:00 |
| 4 | 2011-10-27 00:00:00 |
| 5 | 2011-10-28 00:00:00 |
| 6 | 2011-10-29 00:00:00 |
| 7 | 2011-10-30 00:00:00 |
| 8 | 2011-10-31 00:00:00 |
+----+---------------------+
8 rows in set (0.00 sec)
mysql> select ID ,date from Table_S having count(ID)<3;
Empty set (0.00 sec)mysql> select ID ,date from Table_S where ID not in(select ID from Table_S having count(ID)<3);
+----+---------------------+
| ID | date |
+----+---------------------+
| 1 | 2011-10-24 00:00:00 |
| 2 | 2011-10-25 00:00:00 |
| 3 | 2011-10-26 00:00:00 |
| 4 | 2011-10-27 00:00:00 |
| 5 | 2011-10-28 00:00:00 |
| 6 | 2011-10-29 00:00:00 |
| 7 | 2011-10-30 00:00:00 |
| 8 | 2011-10-31 00:00:00 |
+----+---------------------+
8 rows in set (0.00 sec)