按:来源于平日的工作和学习,不求系统,只求记录,会随时补充。
1. 删除一个已经被作为外键和索引的列,需要两步:
ALTER TABLE `vcmvideo`.`h_hotcontentapply` DROP FOREIGN KEY `FK2F7F418BFFE3FF41` ;
ALTER TABLE `vcmvideo`.`h_hotcontentapply` DROP COLUMN `applyCpId`, DROP INDEX `FK2F7F418BFFE3FF41` ;
2. 查看当前时间
select now(); 取得当前的时间
示例:
mysql> select now();
+---------------------+
| now() |
+---------------------+
| 2011-05-03 21:53:11 |
+---------------------+
1 row in set (0.00 sec)
mysql> select date_format(now(), '%Y%m%d %H:%i%s');
+--------------------------------------+
| date_format(now(), '%Y%m%d %H:%i%s') |
+--------------------------------------+
| 20110503 22:0619 |
+--------------------------------------+
1 row in set (0.00 sec)