Question

The following tsql fails:

IF OBJECT_ID('FDSCorp.XLFILES') IS NOT NULL
BEGIN 
    DELETE FROM FDSCorp.XLFILES;

    INSERT INTO FDSCorp.XLFILES 
       SELECT DISTINCT * FROM dbo.XLFILES;
END
ELSE 
    exec sp_changeobjectowner XLFILES, FDSCorp;

Error:

The image data type cannot be selected as DISTINCT because it is not comparable.

Yes XLFilES has an image column, but in this case FDSCorp.XLFILES doesn’t exist so that distinct code would never get to run.

This code is generated for each table in the database and I know that this section of the code will never be run on a table where it could fail due to the distinct issue.

I really don’t want to have to overcomplicate the code checking for types which I can’t use distinct with if that scenario could never happen in a real situation.

Is there some way I can bypass this check?

Answer 1

The only way to avoid the error is for you to prevent the server from “seeing” the code you don’t want it to compile. Each batch is compiled entirely (including every statement, ignoring control flow) before execution starts:

IF OBJECT_ID('FDSCorp.XLFILES') IS NOT NULL
BEGIN 
    DELETE FROM FDSCorp.XLFILES;

    exec sp_executesql N'INSERT INTO FDSCorp.XLFILES 
       SELECT DISTINCT * FROM dbo.XLFILES;';
END
ELSE 
    exec sp_changeobjectowner XLFILES, FDSCorp;

Now, when this batch is compiled, it won’t attempt to compile the INSERT, since so far as this batch is concerned, it’s just a string literal.