This is something that has been a problem for functions from day one in MySQL Stored Functions. Also from day one AB have known this is a problem and have planned to fix the problem as soon as possible.
I imagine the problem is the way the system works internally and the possiblity that the system could go into an infinite loop when being called in an SQL statement. In Oracle for example you sometimes have to include a purity level in functions to tell the compiler that they won't amend data so they can be safely used in SQL.
I think this will be treated with enough urgency by AB that it will be included sooner rather than later.
It's also a problem in Triggers where this sort of thing is vital (IMO) for the uptake of triggers.
Andrew Gilfrin
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