select * from (select * from a inner jion b on a.name = b.name) ab inner join c on ab.name = c.name
with t as(
select name from a
union all
select name from b
union all
select name from c
)select name from t group by name having count(1)>1;
你是要查某一个表中的重复数据 ,还是三个表都查。