HELP with a Query

[Alex]

Hi,
I need some help with a query.
I use a reference table to lookup some codes. Everything works well if the reference table contains a reference but the query fails if no reference fails (Z.ref_code=123456).
What I need to is either return 0 or null into Z.prim_exch if no reference can be found. Whats the best way to do that ? I tried a sub query but also did not succeed.
SELECT A.sec_code,A.exch_code,A.price_date,Z.prim_exch,
CASE
WHEN A.exch_code = Z.prim_exch THEN 1
ELSE 0
END AS is_prim
FROM price_hist AS A, references AS Z
WHERE A.price_date <= '20040219' AND A.sec_code=123456 AND Z.ref_code=123456 LIMIT 10;

Thanks for any help.
Alex


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[Martijn van Oosterhout]

On Sat, Feb 21, 2004 at 05:20:51PM +0900, Alex wrote:

Hi,
I need some help with a query.
I use a reference table to lookup some codes. Everything works well if the
reference table contains a reference but the query fails if no reference
fails (Z.ref_code=123456). What I need to is either return 0 or null into
Z.prim_exch if no reference can be found. Whats the best way to do that ?I
tried a sub query but also did not succeed.
Lookup an SQL site about OUTER JOINS. Should do what you want.

--
Martijn van Oosterhout <kl*****@svana.org> http://svana.org/kleptog/ If the Catholic church can survive the printing press, science fiction
will certainly weather the advent of bookwarez.
http://craphound.com/ebooksneitherenorbooks.txt - Cory Doctorow

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