The T-SQL language contains numerous functions that you can incorporate into the T-SQL statements that you build. These functions perform a variety of important tasks. The text that follows covers some of the commonly used numeric, string, date/time, and null-related functions. For additional information on the plethora of T-SQL functions available, consult Books On-line.
The IsNumeric function returns information on whether a value is numeric. Here's an example:
SELECT CustomerID, PostalCode, IsNumeric(PostalCode) FROM Customers
The SELECT statement ...