Your IN clause placeholder will only work if there's one value. You either have to dynamically create the query so the number of IN placeholders matches the number of IN bind parameters; or you have to dynamically create the IN clause to expand to what you want.
Huh? The clause 0 <> position(lower(username) IN ?) should return true for as many tuples from usernames match. $message -> {'message'} is a single text value which may or may not contain a user's username. Or am I misunderstanding something here?

Added After reading your link it looks like you misunderstood the question. The foo IN (bar, baz, qux) you're mentioning is different than the position(foo IN bar) I'm using. See String functions and operators for more detail.

Seeking Green geeks in Minnesota

In reply to Re^2: Style: Passing the same value for multiple DBI placeholders by diotalevi
in thread Style: Passing the same value for multiple DBI placeholders by diotalevi

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