Re: Simple Stored Function not working

[Владислав Сокол]

When local variable (including compound statement parameter) name and column name interferes then the variable name is always preferred. Hence your

WHERE businessGroup = businessGroup

compares 2 copies of input variable - i.e. checks that the parameter value provided is not NULL.

You must specify table alias (which is impossible for a variable) for one of the names to be treated as column name:

WHERE vat.businessGroup = businessGroup