Using an iRule to route SQL traffic

The new MS SQL profile in 11.5 allows you to balance across SQL pools based on command (read or write) and user (from a defined list). Beyond this there's no built-in SQL parsing function, so you'd necessarily have to build a pretty complex binary-based iRule, which I wouldn't recommend. That said, if 1) you can define a value early on in the SQL data, and b) that data is in every request (or at least 1 per TCP session), then there's still a chance you could read this and do something useful.