Transact-SQL Reference
ISNUMERIC
Determines whether an expression is a valid numeric type.
Syntax
ISNUMERIC ( expression )
Arguments
expression
Is an expression to be evaluated.
Return Types
int
Remarks
ISNUMERIC returns 1 when the input expression evaluates to a valid integer, floating point number, money or decimal type; otherwise it returns 0. A return value of 1 guarantees that expression can be converted to one of these numeric types.
Examples
A. Use ISNUMERIC
This example returns 1 because the zip column contains valid numeric values.
USE pubs
SELECT ISNUMERIC(zip)
FROM authors
GO
B. Use ISNUMERIC and SUBSTRING
This example returns 0 for all titles in the titles table because none of the titles are valid numeric values.
USE pubs
GO
-- Because the title column is all character data, expect a result of 0
-- for the ISNUMERIC function.
SELECT SUBSTRING(title, 1, 15) type, price, ISNUMERIC(title)
FROM titles
GO
Here is the result set:
type price
--------------- -------------------------- -----------
The Busy Execut 19.99 0
Cooking with Co 11.95 0
You Can Combat 2.99 0
Straight Talk A 19.99 0
Silicon Valley 19.99 0
The Gourmet Mic 2.99 0
The Psychology (null) 0
But Is It User 22.95 0
Secrets of Sili 20.00 0
Net Etiquette (null) 0
Computer Phobic 21.59 0
Is Anger the En 10.95 0
Life Without Fe 7.00 0
Prolonged Data 19.99 0
Emotional Secur 7.99 0
Onions, Leeks, 20.95 0
Fifty Years in 11.95 0
Sushi, Anyone? 14.99 0
(18 row(s) affected)