PostgreSQL IS NOT NULL condition

Preamble

PostgreSQL IS NOT NULL condition is used to check the value of NOT NULL in SELECT, INSERT, UPDATE or DELETE operators.

The syntax for IS NOT NULL condition in PostgreSQL

expression IS NOT NULL

Parameters and arguments of the condition

• expression – A value to check if it is a non-zero value.

Note:

• If the expression is NOT NULL value, the condition is evaluated as TRUE.
• If the expression is NULL, the condition is evaluated as FALSE.

Example of an IS NOT NULL condition with the SELECT operator

Here is an example of how to use PostgreSQL condition IS NOT NULL in SELECT operator:

SELECT *
FROM empls
WHERE first_name IS NOT NULL;

This example of PostgreSQL IS NOT NULL will return all records from the employee table where first_name does not contain the value NULL.

Example of a condition with the INSERT operator

Here is an example of how to use PostgreSQL condition IS NOT NULL in INSERT operator:

INSERT INTO inventory
(inventory_id, item_name)
SELECT product_id, product_name
FROM products
WHERE product_name IS NOT NULL;

This example of PostgreSQL IS NOT NULL will insert records into the inventory table where product_name does not contain a NULL value.

Example of a condition with UPDATE operator

Here is an example of how to use PostgreSQL condition IS NOT NULL in UPDATE operator:

UPDATE inventory
SET status = 'Available'
WHERE item_name IS NOT NULL;

This example of PostgreSQL IS NOT NULL will update records in the inventory table where item_name does not contain an item_name value of NULL.

Example of a condition with the DELETE operator

Here is an example of how to use PostgreSQL condition IS NOT NULL in DELETE operator:

DELETE FROM empls
WHERE archive IS NOT NULL;

This example of PostgreSQL IS NOT NULL will delete all records from the empls table where the archive field does not contain the value NULL.

Postgresql Tutorials: Not Null Constraints in Postgresql – PostgreSQL not null example

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