Question

I am using a try-catch block in T-SQL, and I want to only catch a specific error number. In other cases, I am using RAISERROR() as a poor-man’s re-throw to return error information to the application.

When I try the following, I get an “Incorrect syntax near ‘error_message'” error:

raiserror
    (
         error_message()
        ,1
        ,1
    )

The following, however, works fine:

declare @err varchar(100)
set @err = error_message()

raiserror
    (
         @err
        ,1
        ,1
    )

I thought it might be a typecasting quirk, so I tried this, but that also yielded a syntax error:

raiserror
    (
         cast(error_message() as varchar(100))
        ,1
        ,1
    )

What’s going on here? Why do I have to store the result of ERROR_MESSAGE() in a variable before using it as a parameter to RAISERROR(), instead of calling the function directly?

Answer 1

Below post answers your Question: https://stackoverflow.com/a/3415125/639960

In a nutshell (quoted from above post):

RAISERROR follows the same rules as any other stored procedure call.
Parameters passed in must be a constant or a variable. You cannot pass
a function directly as a parameter.

See Executing Stored Procedures for documentation on this.