时间：2021-09-05 09:45:43 | 栏目：Mysql | 点击：次
1、更新整张表，如果某一行数据的某一列的值为空，那么让他和另一列字段的值相等
UPDATE ot_tgbz set update_day=if(update_day is null,date,update_day);
2、更新整张表，如果某个字段大于2，那么把他们都更新成2；
UPDATE ot_user set xingyun_num=if(xingyun_num > 2,2,xingyun_num);
3、把shop_goods这个表里的thumb字段里的内容中含有https://www.jb51.net/的网址全部替换成空的。
update shop_goods set thumb= replace (thumb,'https://www.jb51.net/','') where thumb like '%https://www.jb51.net/%';
4、sql语句多字段where查询
$map= " CAST(
`UE_account` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_accName` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_truename` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_phone` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'";