On Sun, Jun 20, 2010 at 7:41 PM, P Kishor <punk.k...@gmail.com> wrote:
> Once again, did you try Igor's suggestion? Exactly as he suggested? > Don't know if it will work or not, but this I can say -- if there is > one person in the entire SQL world you should listen to very > carefully, it is Igor. There is never any wasted words in his > suggestion, and his is almost always the correct solution. Try it, > then report back. With respect to Igor, you are not going to find anyone that stands up and listens to EXACTLY what he said faster than I do! Igor was absolutely vital in my understanding of some Windows COM development which is a corner stone of my application. I only wish I knew a small faction of what he knows! With that said, I did try exactly what he said, I think. Here is what I tried: SELECT FolderId, ImageId, instertedon FROM V_FAVORITES_SELECTED WHERE case when instertedon > julianday(@time) then findLargeImage(@path, FolderId, ImageId) else 0 end; I am getting the same results as I did with my query, it is running through the whole result set, calling the extended function on each row. > iirc, LIMIT 1 is applied *after* the WHERE clause is satisfied. In > other words, the entire result set is returned, and then it is > LIMITed. So, the behavior is correct. I know there is a huge amount of math and science behind how SQL optimizers work, so I am looking for a better understanding of how things work: Why can't the optimizer use the LIMIT X as a way to short-circuit the building of the WHERE clause? It seems logical, but since that is not the case, I am sure there is a reason why it isn't the case, does anyone know that reason or can provide me an example of why the WHERE clause needs to be fully satisfied first? Sam _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
