mysql> select left(now(),7);
+---------------+
| left(now(),7) |
+---------------+
| 2010-09 |
+---------------+
1 row in set (0.00 sec)
mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2010-09-21 13:40:37 |
+---------------------+
1 row in set (0.00 sec
+---------------+
| left(now(),7) |
+---------------+
| 2010-09 |
+---------------+
1 row in set (0.00 sec)
mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2010-09-21 13:40:37 |
+---------------------+
1 row in set (0.00 sec
select left(FTime,10),count(*) from Tbl_User group by left(FTime,10) ;
+----------------+----------+
| left(FTime,10) | count(*) |
+----------------+----------+
| | 1044 |
| 2010-07-21 | 6 |
| 2010-07-22 | 2746 |
| 2010-07-23 | 10273 |
| 2010-07-24 | 7691 |
| 2010-07-25 | 6955 |
| 2010-07-26 | 7622 |
| 2010-07-27 | 2130 |
+----------------+----------+
注意下面查询语句的区别：
mysql> select left(FTime,10),count(*) from Tbl_User group by left(FTime,10) ;
+----------------+----------+
| left(FTime,10) | count(*) |
+----------------+----------+
| | 1 |
| 2010-07-13 | 7 |
| 2010-07-14 | 1 |
| 2010-07-15 | 1 |
| 2010-07-16 | 3 |
| 2010-07-20 | 2 |
| 2010-07-25 | 1 |
+----------------+----------+
7 rows in set (0.00 sec)
mysql> select FTime,count(*) from Tbl_User group by left(FTime,10) ;
+---------------------+----------+
| FTime | count(*) |
+---------------------+----------+
| | 1 |
| 2010-07-13 11:39:45 | 7 |
| 2010-07-14 11:50:20 | 1 |
| 2010-07-15 15:16:20 | 1 |
| 2010-07-16 16:11:39 | 3 |
| 2010-07-20 12:00:31 | 2 |
| 2010-07-25 19:16:08 | 1 |
+---------------------+----------+
FTime类型如下：
`FTime` varchar(32) collate utf8_bin NOT NULL,
作者：jackxiang@向东博客 专注WEB应用 构架之美 --- 构架之美，在于尽态极妍 | 应用之美，在于药到病除
地址：http://jackxiang.com/post/3337/
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最后编辑： jackxiang 编辑于2010-9-21 13:42
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