SQL non Equi Join

Description

The SQL NON EQUI JOIN uses comparison operator instead of the equal sign like >, <, >=, <= along with conditions.

Syntax:

SELECT * 
FROM table_name1, table_name2 
WHERE table_name1.column [> |  < |  >= | <= ] table_name2.column;

Pictorial representation:

Example:

Here is an example of non equi join in SQL between two tables

Sample table: orders

Sample table: customer

To get order number and order amount columns from orders table aliased as 'a' and customer name and working area columns from customer table aliased as 'b' after joining said two tables with the following condition -

1. order amount of orders table matches any of the opening amounts of customer table,

the following SQL statement can be used:

SQL Code:

SELECT a.ord_num,a.ord_amount,b.cust_name,b.working_area 
FROM orders a,customer b 
WHERE a.ord_amount 
BETWEEN b.opening_amt AND b.opening_amt;

Output:

  ORD_NUM ORD_AMOUNT CUST_NAME                                WORKING_AREA
--------- ---------- ---------------------------------------- -------------
   200110       3000 Micheal                                  New York
   200101       3000 Micheal                                  New York
   200108       4000 Cook                                     London
   200119       4000 Cook                                     London
   200113       4000 Cook                                     London
   200108       4000 Karl                                     London
   200119       4000 Karl                                     London
   200113       4000 Karl                                     London

Key points to remember

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