Home Forums Article Discussions Article Discussions by Author Discuss content posted by Richard Rozema Combining union and union all RE: Combining union and union all

  • March 8, 2012 at 2:39 am

    #1456406

    R.P.Rozema (3/8/2012)

    tim.kay (3/8/2012)

    Got it right and thought that I understood - now looking at the other posts I am slightly confused.

    So am I, as I was very sure I had tested both situations: union followed by union all and union all followed by union... I see what happens, but it contradicts with my previous results. So I need to find out what I did wrong previously.

    Your test is wrong because of values used:

    1, 2 and 3 are different and they are not affected by the DISTINCT of UNION.

    You should use same values!

    😉