having在Oracle和mysql中的一点不同点

2321ewq

  在Oracle中，having一定要结合group by使用，但在mysql中，情况就不一样了，可以单独使用。C:\Documents and Settings\guogang>sqlplus test/test
SQL*Plus: Release 10.2.0.1.0 - Production on 星期二 8月 12 09:09:58 2014
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

SQL> select * from test1  having owner ='SYS';
select * from test1  having owner ='SYS'
                         *
第 1 行出现错误:
ORA-00979: 不是 GROUP BY 表达式


SQL> select owner,count(1) from test1  group by owner having owner ='SYS';
OWNER                            COUNT(1)
------------------------------ ----------
SYS                                 30754


mysql> select * from test having id>98;
+------+-------------+
| id   | create_time |
+------+-------------+
|   99 | 2014-08-12  |
|  100 | 2014-08-12  |
+------+-------------+
2 rows in set (0.00 sec)

mysql> select id,count(1) from test group by id having id>98;
+------+----------+
| id   | count(1) |
+------+----------+
|   99 |        1 |
|  100 |        1 |
+------+----------+
2 rows in set (0.00 sec)