Question

SQL设计,一道题SPJ的零件工程供应库，其中包含供应商表S、零件表P、工程表J、供应情况表SPJ。请用SQL语言完成下

Answer 1

select * from s where sno in (

select sno from (

select pno, sno from spj

group by pno, sno

) ta

having count(*) > 3

)