SQL Server ISNUMERIC() Function: Check Numbers

SQL Server ISNUMERIC() function determines whether the given expression is a valid numeric type.

ISNUMERIC(input_expression)

Parameters

input_expression: A value or an expression to be checked as number or not.

Return Value

Returns an integer type. ISNUMERIC returns 1 if the input expression is a valid numeric expression, else it returns 0.

SQL Server valid numeric data types include int, smallint, bigint, tinyint, bit, decimal, numeric, float, real, money, smallmoney.

Note: the ISNUMERIC() returns 1 for some non-numeric characters like a plus (+), minus (-), and some currency symbols like a dollar sign ($).

Example 1:

The following ISNUMERIC() function checks if the passed value is of number type or not. It returns 1 if it is a number.

SELECT ISNUMERIC(1234) AS Result;

The ISNUMERIC() returns 0 if the passed value is non-numeric.

SELECT ISNUMERIC ('Hello') AS Result;

You can also use the ISNUMERIC() function with a currency value like a dollar sign ($). It considers it as numeric and returns 1.

SELECT ISNUMERIC ($25) AS Result;

It considers the negative number as numric value.

SELECT ISNUMERIC(-4) AS Result;