MySQL ifnull simple instructions for use

About MySQL ifnull functions

The MySQL IFNULL function is one of the MySQL control flow functions that accepts two parameters, and if not NULL , returns the first argument. Otherwise, the IFNULL function returns a second argument.

Two parameters can be literal values or expressions.

The IFNULL syntax of the function is described below:

IFNULL(expression_1,expression_2);

If expression_1 not NULL , the IFNULL function returns, expression_1 otherwise returns expression_2 the result.

IFNULLThe function returns a string or number based on the context used.

MySQL's ifnull function example

See the following IFNULL function example:

Example-1

SELECT IFNULL(1,0); -- returns 1

Example-2

SELECT IFNULL(‘‘,1); -- returns ‘‘

Example-3

SELECT IFNULL(NULL,‘IFNULL function‘); -- returns IFNULL function

Example -4

SELECT Ifnull (Sex,'as fromuser-- If the query to this sex is a null value, then the value is assigned to an empty string

How does the statement in the above example work?

• IFNULL(1,0)Returned 1 because it is 1 not NULL .
• IFNULL(‘‘，1)Returns ‘‘ because the ‘‘ string is not NULL .
• IFNULL(NULL，‘IFNULL function‘)Returns a IFNULL function string because the first argument is NULL .

MySQL ifnull simple instructions for use