mysql中处理特殊sql语句的实例教程

UPDATE ot_tgbz set update_day=if(update_day is null,date,update_day);

UPDATE ot_user set xingyun_num=if(xingyun_num > 2,2,xingyun_num);

update shop_goods  set thumb= replace (thumb,'http://www.jb51.net/','') where thumb like '%http://www.jb51.net/%';

$map= " CAST(
  `UE_account` AS CHAR CHARACTER
     SET utf8
  ) LIKE '%$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%'";