[GENERAL] Wait, not solved... Was (Return t/f on existence of a join)

[Madison Kelly]

Madison Kelly wrote:
Thanks to both of you, Erik and Jon!
  I had to tweak your two replies to get what I wanted (all 'foo' rows 
returned, was only getting ones with a match in 'baz'). You two sent me 
on the right path though and I was able to work out the rest using the 
PgSQL docs on 'CASE' and 'JOIN'.

  Here is the working query (where 'bar_id'=2):

SELECT
    CASE z.baz_bar_id
    WHEN 2
        THEN TRUE
        ELSE FALSE
    END AS tf_col,
    f.foo_id
FROM foo f
    LEFT OUTER JOIN baz z
    ON (f.foo_id=z.baz_foo_id)
    LEFT OUTER JOIN bar b
    ON (b.bar_id=z.baz_bar_id)
AND
    b.bar_id=2;

  Thanks kindly to both! I honestly didn't expect to work this out 
before then end of the day. Cool!

Madi

Doh!

  It's returning a row from 'foo' for every entry in baz that has an 
entry pointing to foo (possibly same problem with each pointer to an 
entry in bar, not sure yet). The 'true/false' part is working though...

Back to reading. *sigh* :)

Madi

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