关系操作所对应的sql语句

--并---------------------------
select * from R
union
select * from S
--交---------------------------
select * from R
  where exists (select * from S
                  where R.A=S.A AND R.B=S.B AND
                          R.C=S.C)
--差---------------------------
select * from R
  where not exists (select * from S
                      where R.A=S.A AND R.B=S.B AND
                          R.C=S.C)
--笛卡尔积-----------------------------
select * from R,S
--选择---------------------------------
select * from Student where Sdept='IS'
--投影---------------------------------
select Sname,Sdept from Student
--连接(等值)---------------------------
select * from R join S on R.A = S.A --R表A等S表C
--连接(自然)---------------------------
select distinct * from R join S on R.A = S.A
--连接(左外)---------------------------
select * from R left join S on R.A = S.A
--连接(右外)---------------------------
select * from R right join S on R.A = S.A
--连接(全)-----------------------------
select * from R full join S on R.A = S.A