Fun with GO and Preventing SQL Batches from Parsing

Solomon Rutzky has an apropos post for Friday the 13th:

In a previous post, Prevent Full Script Execution (Understanding and Using PARSEONLY and NOEXEC), I explained how to easily disable a script using the PARSEONLY session setting. That same method can be used to disable one or more sections within a script instead of the entire script. But in either case, “disabling” doesn’t mean that the script, or section of code, will be skipped entirely as if it wasn’t there. It will still be parsed by SQL Server as that is not something that can be turned off. This means that you could still see parsing errors related to undeclared variables, syntax errors, etc.

Then one day I tried something silly that I figured wouldn’t work but wanted to try anyway (because quite often you don’t know until you know), and it actually did work (for the most part). I found a way to fully disable an entire T-SQL batch, and there really isn’t any indication that it happened. However, this “technique” is more limited than PARSEONLY as it only works on individual batches, and it only works in some environments.

Read on to see how you can use the GO operator to prevent many SQL Server client tools from even noticing a block of text.