mysql之多表操作

*、mysql之多表查询某些共性特定列

select a.oid as oid,a.en_name as enname,a.name as name from p_n a where 1=1
union
select  a.oid as oid,a.enname as enname,a.cnname as name from p_f a where 1=1

*、mysql之多表查询某些共性特定列的数据总和

select c.oid , c.enname , c.name from (
select a.oid as oid,a.en_name as enname,a.name as name from p_n a where 1=1
union
select b.oid as oid,b.enname as enname,b.cnname as name from p_f b where 1=1
) c;
升级为
select count(*) from (
select a.oid as oid,a.en_name as enname,a.name as name from p_n a where 1=1
union
select b.oid as oid,b.enname as enname,b.cnname as name from p_f b where 1=1
) c;