[SQL Server] Simple ISNUMERIC Test

[SQL Server] Simple ISNUMERIC Test

ISNUMERIC System function returns 1(true) when the expression is a valid numeric type.

Script

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SELECT ISNUMERIC('1234') AS '1', ISNUMERIC('A587') AS '2', ISNUMERIC('222!') AS '3', ISNUMERIC('123l123') AS '4', ISNUMERIC('157.123') AS '5', ISNUMERIC(NULL) AS '6', ISNUMERIC('') AS '7', ISNUMERIC('0') AS '8', ISNUMERIC('12345678901234567890') AS '9', ISNUMERIC('1234567890123456789012345678901234567890123456789012345678901234567890') AS '10', ISNUMERIC('1.234567890123456789012345678901234567890123456789012345678901234567890') AS '11';

Result

Description

1. Returns "1".
2. Includes a character - A. Returns "0"
3. Includes a special character - !. Returns "0"
4. Includes a character (looks like 1, but it's not) - l. Returns "0"
5. Returns "1"
6. NULL does not regard as a numeric type. Returns "0".
7. Blank does not regard as a numeric type. Returns "0".
8. Returns "1".
9. It's bigger than BIGINT type, but still a numeric type. Returns "1"
10. Very big number(70 digits), but still a numeric type. Returns "1"
11. 69 places of decimals, but still a numeric type. Returns "1"

Reference

• ISNUMERIC (Transact-SQL): https://docs.microsoft.com/en-us/sql/t-sql/functions/isnumeric-transact-sql?view=sql-server-ver15