On 14 Jul 2010, at 7:22pm, Richard Hipp wrote: > On Wed, Jul 14, 2010 at 1:25 PM, Simon Slavin <slav...@bigfraud.org> wrote: > >> By the way, can someone explain why this rule, equivalent to line 4 of the >> table, is there: >> >> else if the right op contains NULL, then IN = NULL > > NULL should be interpreted as "unknown". Hence in: > > 5 IN (1,2,3,4,NULL,6,7) > > we do *not* definitely know that 5 is not in the RHS.
Wow. I'd never have guessed that. Thanks to both Dan and Richard for fast answers. That makes both the table and the test-set I suggested far more easy to understand. Perhaps that explanation could be included in the explanation of 'IN'. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
