NULLIF() - MySQL Control Flow Function

The MySQL NULLIF() function is a control flow function that returns NULL if two expressions are equal, otherwise, it returns the first expression. In this tutorial, we'll discuss the syntax, usage, and examples of the MySQL NULLIF() function.

Syntax

The syntax of the MySQL NULLIF() function is as follows:

NULLIF(expression1, expression2)

Where expression1 and expression2 are the expressions to compare. If both expressions are equal, the function returns NULL. Otherwise, it returns the value of expression1.

Example

Let's consider the following example:

SELECT NULLIF(1, 1);

The output of the query will be:

NULL

In this example, the NULLIF() function is used to compare the values 1 and 1. Since both are equal, the function returns NULL.

Explanation

The MySQL NULLIF() function compares two expressions and returns NULL if they are equal, otherwise, it returns the value of the first expression. This is useful when you want to handle null or equivalent values in a special way, such as replacing them with another value.

Use

The MySQL NULLIF() function can be used in a variety of scenarios, such as:

• Replacing null or equivalent values with another value.
• Handling divide-by-zero errors.

Important Points

• The NULLIF() function returns NULL if the two expressions are equal, otherwise, it returns the value of the first expression.
• The data types of the two expressions must be compatible.
• The NULLIF() function can be used with any valid MySQL expression.

Summary

In this tutorial, we discussed the MySQL NULLIF() function, which is a control flow function that returns NULL if two expressions are equal, otherwise, it returns the first expression. We covered the syntax, examples, explanation, use cases, and important points of the NULLIF() function. With this knowledge, you can use NULLIF() effectively in your MySQL queries to handle null or equivalent values in a special way.