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) 求解这样的sql语句如何写?? update 为什么不修改数据了?急啊大家看看 如何解决 ./bin/my_print_defaults: cannot execute binary file mysql 更新错误怎么恢复 在mysql中动态建立表,数据库表如果达到10000个,合理吗? 在C#中如何访问mysql,是不是必须要建立数据源?否则该怎么做,谢谢 mysql 基础问题,谢谢 mysql的事务中怎么打印出异常信息 mysql该怎么监视修改该条的时间啊 mysql递归查询统计 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)