concat(A,B,C,...)  拼接字符串

例如concat('123','***','345')  =>123***345

SELECT    concat(        substr(t1.CODE, 1, 3),        '****',        substr(t1.CODE, 8)    ),    t1.CODE,    t2.TITLEFROM    table1 t1LEFT JOIN table2 t2 ON t1.table2id = t2.idWHERE    t1..CREATEDATE >= '2016-07-19 00:00:00'AND t1.CREATEDATE <= '2016-07-19 23:59:59';

两张表字段模糊匹配，进行数据更新：

update tb1 join tb2 on tb1.a like concat('%',tb2.a,'%')set tb1.xx=tb2.xxwhere xxx;