On Feb 20, 2012, at 9:34 AM, Igor Tandetnik wrote: > Puneet Kishor <punk.k...@gmail.com> wrote: >> But, why is #5 329743 and not 329686? Where are the extra 57 rows coming >> from? I thought a LEFT JOIN was supposed to include >> *all* the rows from the left table with NULLs for the columns of the right >> table where there was no match. So, at most, the >> resulting table would have as many rows as the rows in the left table. >> Certainly not more. > > The conclusion doesn't follow from the premise. Yes, a row from the left > table is included in the resultset even if there are no matching rows in the > right table. Which means that the resultset would contain *at least* as many > rows as there are in the left table - but it certainly may contain more. For > each row in the left table that has N matching rows in the right table (with > N > 0), there will be N rows in the resultset.
Thanks for the great explanation. Now, the follow up question -- is there are way to force the query to return only the "first" match so the resulting query has only as many rows as the left table? -- Puneet Kishor _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
