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PostgreSQL - Comparison Operators
Consider the table COMPANY having records as follows −
testdb=# select * from COMPANY; id | name | age | address | salary ----+-------+-----+-----------+-------- 1 | Paul | 32 | California| 20000 2 | Allen | 25 | Texas | 15000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall| 45000 7 | James | 24 | Houston | 10000 (7 rows)
Here are simple examples showing the usage of PostgresSQL Comparison Operators.
Here, we have used the WHERE clause, which will be explained in a separate chapter, but for now, you can understand that the WHERE clause is used to put a conditional statement along with the SELECT statement.
The following SELECT statement lists down all the records having SALARY greater than 50,000.00 −
testdb=# SELECT * FROM COMPANY WHERE SALARY > 50000;
The above given PostgreSQL statement will produce the following result −
id | name | age |address | salary ----+-------+-----+-----------+-------- 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 (2 rows)
The following SELECT statement lists down all the records having SALARY equal to 20,000.00 −
testdb=# SELECT * FROM COMPANY WHERE SALARY = 20000;
The above given PostgreSQL statement will produce the following result −
id | name | age | address | salary ----+-------+-----+-------------+-------- 1 | Paul | 32 | California | 20000 3 | Teddy | 23 | Norway | 20000 (2 rows)
The following SELECT statement lists down all the records having SALARY not equal to 20,000.00 −
testdb=# SELECT * FROM COMPANY WHERE SALARY != 20000;
The above given PostgreSQL statement will produce the following result −
id | name | age | address | salary ----+-------+-----+-------------+-------- 2 | Allen | 25 | Texas | 15000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000 (5 rows)
The following SELECT statement lists down all the records having SALARY not equal to 20,000.00 −
testdb=# SELECT * FROM COMPANY WHERE SALARY <> 20000;
The above given PostgreSQL statement will produce the following result −
id | name | age | address | salary ----+-------+-----+------------+-------- 2 | Allen | 25 | Texas | 15000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000 (5 rows)
The following SELECT statement lists down all the records having SALARY greater than or equal to 65,000.00 −
testdb=# SELECT * FROM COMPANY WHERE SALARY >= 65000;
The above given PostgreSQL statement will produce the following result −
id | name | age | address | salary ----+-------+-----+-----------+-------- 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 (2 rows)