sqlcmd swallows errors by default

I'm sure this is well-known out in SQL land, but I keep forgetting about it, so I'm writing this short post as a way to cement the knowledge in my brain: sqlcmd, the current command line utility for running T-SQL and replacement for OSQL, does not return a DOS ERRORLEVEL > 0 by default, even when the command being executed fails.

You need to pass the -b flag to raise an ERRORLEVEL 1 when a real error (SQL error severity > 10) occurs, which is crucial when running batch jobs in job systems that report status based on DOS ERRORLEVELs.