Hi, I understand that I should also use varno to check which table is referenced by varattno. In case of Join, aggregation, etc. Sometimes I get a number or INNER_VAR or OUTER_VAR. I am lost on how i could resolve this. I understand that OUTER_VAR/INNER_VAR are related to joins sub plans. Is outer related to left plan and inner to right plan ? In this case varattno is index of target list of subplan ? When varno is an index how to retrieve table info ? Regards Mathieu
Le jeu. 28 juin 2018 à 23:17, Laurenz Albe <laurenz.a...@cybertec.at> a écrit : > Mathieu PUJOL wrote: > > I'am writing a foreign data wrapper. To avoid returning data for a > column that is not used, I parse 'targetlist' and 'qual' of the Plan. > > I'am able to find Var nodes but I can't figure out how i could now if > this node is related to a column my foreign table. > > For a Var v, v->varattno contains the attribute number of the column. > That is the same as the attnum column in pg_attribute. > > If v->varattno == 0, it is a whole-row reference, like in > > SELECT mytab FROM mytab; > > Yours, > Laurenz Albe > -- > Cybertec | https://www.cybertec-postgresql.com >
