Return LEFT JOINed tables when one has no matching column

[Madison Kelly <linux@xxxxxxxxxxx>]

Hi all,

  I've got a variation on a question I asked some time ago... I've got 
a table that is simply a collection of "variable" -> "value" columns 
with a pointer to another table. I use this as little as possible, given 
how much of a headache it is, but I've run into a situation where I need 
to pull something from it in a JOIN query. Trick is, the column 
'variable' may simply not exist, but I want the rest of the query to 
return and let it be NULL.

  Specifically, I've got a query like this:

SELECT
	a.tbl1_name,
	b.tbl2_date,
	c.tbl3_value AS some_value
FROM
	table_1 a
LEFT JOIN
	table_2 b ON (a.tbl1_id=b.tbl2_tbl1_id)
LEFT JOIN
	table_3 c ON (a.tbl1_id=c.tbl3_tbl1_id)
WHERE
	c.tbl3_variable='some_variable'
AND
	a.tbl1_id=123;

  I want the data from table_1 and table_2 to return and table_3 to 
return NULL when there is no matching c.tbl3_variable='some_variable'. 
Is this possible?

Thanks as always!

Madi

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