Multiple table operations in mysql

*, MySQL's many tables to query some common specific columns

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 as many tables to query the sum of the data of some common specific columns

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;
upgrade to
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;