On Tue, Jul 30, 2019 at 02:43:05PM -0700, 毛瑞嘉 wrote: > Hi, > > > I wrote a patch for adding CORRESPONDING/CORRESPONDING BY to set operation. > It is a task in the todo list. This is how the patch works: > > > I modified transformSetOperationStmt() to get an intersection target list > which is the intersection of the target lists of the left clause and right > clause for a set operation statement (sostmt). The intersection target list > is calculated in transformSetOperationTree() and then I modified the target > lists of the larg and rarg of sostmt to make them equal to the intersection > target list. Also, I also changed the target list in pstate->p_rtable in > order to make it consistent with the intersection target list. > > > I attached the scratch version of this patch to the email. I am not sure > whether the method used in the patch is acceptable or not, but any > suggestions are appreciated. I will add tests and other related things to > the patch if the method used in this patch is acceptable.
I tried adding documentation based on what I could infer about the behavior of this patch. Is that documentation correct? Best, David. -- David Fetter <david(at)fetter(dot)org> http://fetter.org/ Phone: +1 415 235 3778 Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate