Thank you! Unfortunately, however, after having stared hard at this diagram for some time, I still fail to grasp what you mean. To stick with the nice railroad metaphor, I'll refer to "tracks" 1 (the topmost route) to to 4 (the bottommost route). What I can see is that: In track 1, "table-name" is followed by an optional "AS table-alias". In track 2, "table-function-name (expr, ...)" is followed by an optional "AS table-alias". In track 3, "(table-or-subquery, ...)", alternatively, "(join-clause)", is not followed by anything. In track 4, "(select-stmt)" is followed by an optional "AS table-alias". The track where I would (still, even after thinking hard) expect this behaviour to be documented is track 3. What am I overlooking?