PostgreSQL Non-Equi Join | PostgreSQL Tutorials and Solutions

PostgreSQL Non-Equi Join performs when 2 tables are not sharing a common column. This join is not based on equal operator. It is based on >=,<=, or between operator.

PostgreSQL Non-Equi Join Examples:

Tables used for below examples:

emp table:

salgrade table:

 grade | lowsal | highsal
-------+--------+---------
     1 |   1000 |    2000
     2 |   2000 |    3000
     3 |   3000 |    4000
     4 |   4000 |    5000

1. Display employees empno, name, salary and their grades.

select e.empno,e.ename,e.sal,s.grade from emp e, salgrade s where e.sal between s.lowsal and s.highsal;

PostgreSQL Non-Equi Join

2. Display employees empno, name, salary and their department names and grades.

select e.empno, e.ename,e.sal,d.dname,s.grade from emp e join dept d on e.deptno=d.deptno join salgrade s on e.sal between s.lowsal and s.highsal;

 empno | ename  |   sal   |   dname    | grade
-------+--------+---------+------------+-------
  7521 | WARD   | 1250.00 | SALES      |     1
  7369 | SMITH  | 1300.00 | RESEARCH   |     1
  7654 | MARTIN | 1250.00 | SALES      |     1
  7934 | MILLER | 1800.00 | ACCOUNTING |     1
  7499 | ALLEN  | 1600.00 | SALES      |     1
  7566 | JONES  | 2975.00 | RESEARCH   |     2
  7698 | BLAKE  | 2850.00 | SALES      |     2