On Sun, Oct 03, 2010 at 02:54:41PM -0400, Frank Bax wrote: > Whatever clause I choose to add I *must* ensure that final result set > contains only one-to-one join between tables. Either of these two > results is acceptable: > > For option 1; result C=All or C=Centre is acceptable. > For option 2; result B=NE70 or B=NE75 or B=NE80 is acceptable. > > I am lost trying to construct SQL to accomplish this...
Try DISTINCT ON, after ensuring the results are ordered meaningfully. http://www.postgresql.org/docs/current/interactive/sql-select.html#SQL-DISTINCT -- Joshua Tolley / eggyknap End Point Corporation http://www.endpoint.com
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