If the grouping inside CTE is executed, I don't think it would generate result like
src_id | dest_id | dist --------+---------+------ 3384 | 6236 | 1 3384 | 1739 | 2 3384 | 6236 | 3 3384 | 1739 | 4 3384 | 6236 | 5 3384 | 1739 | 6 3384 | 6236 | 7 3384 | 1739 | 8 3384 | 6236 | 9 3384 | 1739 | 10 3384 | 6236 | 11 for we have min(dist), so it should be like src_id | dest_id | dist --------+---------+------ 3384 | 6236 | 1 3384 | 1739 | 2 other values will be eliminated by min(). It actually generate no new tuples and the iteration should stop. Best, Jing On Tue, Nov 5, 2013 at 9:28 AM, Albe Laurenz <laurenz.a...@wien.gv.at>wrote: > Jing Fan wrote: > > Why the one inside does not do anything? It won't be executed? > > It is executed. > > It might filter out the occasional row, but if you look at > the example I gave you, you'll see that it won't do anything > to keep it from recursing. > > Yours, > Laurenz Albe >
