SQL基础1

1、多条记录单独更新

需求：有个表（mcs_facility_gx）的字符型字段mf_id，将里面最前面两个字符改为51，比如“45000000140011”，改为“51000000140011”。

update mcs_facility_gx mfg,(SELECT id,CONCAT('51',(substring(mf_id,3))) id2 from mcs_facility_gx) mm set mfg.mf_id = mm.id2 where mfg.id = mm.id;

2、A表插入到B表，表结构一样

insert into scorebak select * from socre where neza='neza'   --插入一行,要求表scorebak 必须存在
select *  into scorebak from score  where neza='neza'  --也是插入一行,要求表scorebak 不存在