On Sun, Feb 20, 2022 at 12:31:22PM +0200, Markur Sens wrote: > > > > Maybe you could rely on some old grammar hack to have something a bit > > similar, > > as (expr).funcname is an alias for funcname(expr). For instance: > > Is this documented & expected behavior or it’s just happens to work?
I don't think it's documented but it's an expected behavior, see https://github.com/postgres/postgres/blob/master/src/backend/parser/parse_func.c#L57-L88 /* * Parse a function call * * For historical reasons, Postgres tries to treat the notations tab.col * and col(tab) as equivalent: if a single-argument function call has an * argument of complex type and the (unqualified) function name matches * any attribute of the type, we can interpret it as a column projection. * Conversely a function of a single complex-type argument can be written * like a column reference, allowing functions to act like computed columns. * * If both interpretations are possible, we prefer the one matching the * syntactic form, but otherwise the form does not matter. * * Hence, both cases come through here. If fn is null, we're dealing with * column syntax not function syntax. In the function-syntax case, * the FuncCall struct is needed to carry various decoration that applies * to aggregate and window functions. [...]
