From: Larry Martell
Date: December 11 2012 9:19pm
Subject: Help with left outer join
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I have this query:

SELECT data_target.name, ep, wafer_id, lot_id,
       date_time, data_file_id, data_cstimage.name,
       bottom, wf_file_path_id, data_measparams.name,
       vacc, data_category.name
FROM data_cst, data_target, data_cstimage, data_measparams,
     data_category, data_tool
WHERE data_cst.target_name_id IN (38018, 29947, 28330)
AND data_cst.date_time BETWEEN '2012-09-01 00:00:00' AND '2012-09-07 00:00:00'
AND data_target.id = data_cst.target_name_id
AND data_cstimage.id = data_cst.image_measurer_id
AND data_measparams.id = data_cst.meas_params_name_id
AND data_category.id = data_tool.category_id
AND data_tool.id = data_cst.tool_id
ORDER BY target_name_id, ep, wafer_id, lot_id, date_time

My problem is that when data_cst.image_measurer_id is NULL I don't get
that data_cst row even though all the other part of the where clause
are TRUE. I understand why that is, but in that case I want the row,
but with NULL in the data_cstimage.name column. I think I need a left
outer join, but I've been messing with this for hours, and I can't get
the syntax right. I've googled it, but all the examples are simple
with just 2 tables. Can someone help me with this?

TIA!
-larry