SQL Server ISNUMERIC() Function

The ISNUMERIC() function in SQL Server checks if a given expression can be converted to a numeric data type. This is extremely useful for data validation, ensuring that values intended to be numbers are actually in a numeric format.

ISNUMERIC(): Definition and Usage

ISNUMERIC() is a valuable tool for cleaning and preparing data. It helps you identify non-numeric entries that might cause errors in your queries or calculations. It returns 1 if the expression can be interpreted as a number, and 0 otherwise.

Syntax


ISNUMERIC(expression)

Parameter Values

Parameter	Description
`expression`	The expression you want to check. This can be a literal value (number or string), a column name, or a more complex expression. This is required.

Examples

Testing a Numeric Literal

Checking if a number is numeric (it is!).

Syntax


SELECT ISNUMERIC(4567);

Output

Testing a Numeric String

Checking if a string representing a number is numeric (it is!).

Syntax


SELECT ISNUMERIC('4567');

Output

Testing Non-Numeric Text

Checking if a text string is numeric (it's not!).

Syntax


SELECT ISNUMERIC('Hello world!');

Output

Testing a Numeric Expression

Checking if a simple calculation is numeric (it is!).

Syntax


SELECT ISNUMERIC(20 * 3);

Output

Testing a Date String

A date string is not considered numeric by `ISNUMERIC()`.

Syntax


SELECT ISNUMERIC('2017-08-25');