oracle数据库sql语句之join实例讲解
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2022-04-08 10:40:39
--group by
select deptno,count(*) from emp group by deptno;
--group by ... having
selec...
--group by
select deptno,count(*) from emp group by deptno;
--group by ... having
select deptno, count(*) from emp group by deptno having count(*)>=5;
--join
select * from emp join dept on emp.deptno = dept.deptno;
--join right
select * from emp right join dept on emp.deptno = dept.deptno;
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