Integration Services Gotcha #6631984: The Table Variable Data Flow Affair

I encountered a teeny little SSIS glitch today that completely did my head in for a good 30 minutes. Ok, I'll admit it, more like an hour.

In my data flow, I had an OLEDB Source which declared and populated a table variable then returned some data, which included a join on my table variable.

The source query worked perfectly, returning plenty of data when tested through SSMS. As soon as I ran the data flow, it would be successful but zero data.

That freakin' table variable was messin' with me. Took it out, replaced it with a subquery and whammo! Data.

Oh SSIS, you pernickety old man, you!