On Friday, 1 November, 2019 10:20, Simon Slavin <slav...@bigfraud.org> wrote:
>On 1 Nov 2019, at 4:17pm, Simon Slavin <slav...@bigfraud.org> wrote: > WHERE (c1 IS NULL) OR (C1 != 2) > which could quite reasonably return rows. However, the NULL possibility > may be redundant. I can't tell without tests. The expression NOT (c1 IS NOT NULL AND c1 == 2) is equivalent to c1 IS NULL OR c1 != 2 is equivalent to (c1 IS NOT 2) or the original proper expression NOT (C1 IS 2) and arises from the use of the '==' and '!=' rather that IS and IS NOT, and generating work-arounds to handle NULLs. Work-arounds for handling NULLs are only required for non-equality tests since there is no standard operators handling nulls for the other comparison operators > < >= <= -- The fact that there's a Highway to Hell but only a Stairway to Heaven says a lot about anticipated traffic volume. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
