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SQL question-- Alternatives to IN statement (nested SQL)

Posted on 2004-08-09
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Last Modified: 2006-11-17
OK, in the absence of a successful mySQL 4.1 installation, I need to know some alternatives to using nested SQL statements.

here's the SQL I have now that is symptomatic of what I need to change:

SELECT field, field, field, field FROM tblcomp WHERE compID IN (SELECT compID_Inv FROM tblinv WHERE mfgID = 56;) ORDER BY CompanyName ASC;

tblcomp = company table
tbl inv = Inventory table

Each company could potentially own SEVERAL machines (held in the tblinv table), but all I WANT is ONE record for each company.  But when I use distinct keyword or DISTINCTROW or a LEFT join I still get multiple company records-- In the above example, it is grabbing a list of all companies that own a machine from a specific manufacturer (mfgID).  The IN statement works great-- but in mySQL it can't handle the nested query.  

Does ANYONE know a way to get the list either with a rewritten single SQL select statement or using a HEAP table?

Thanks!!

norm
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Question by:normenclature
5 Comments
 
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Expert Comment

by:ldbkutty
ID: 11758571
>> OK, in the absence of a successful mySQL 4.1 installation,
wasn't PHPMyAdmin helped you ?

if i understood correctly,

>> The IN statement works great-- but in mySQL it can't handle the nested query.
IN Query supports SubQueries.

>> but all I WANT is ONE record for each company.

Give    LIMIT 1    at the end of the Query.
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LVL 1

Accepted Solution

by:
burritoboy1227 earned 2000 total points
ID: 11763571
i had the same problem just the other day.  even after scouring throught the mysql manuals, i wasn't able to find a single SQL query that would solve this problem (i'm using mysql 4.0)...  so this is what i did.

1. create a temporary table with all the fields you need to select, and make compID the primary key.
2. do a replace into query, i.e.

replace into temp select tblcomp.compID, field, field, field from tblcomp, tblinv where tblcomp.compID=tblinv.compID_Inv AND tblinv.mfgID=56;

mysql will automatically blast all the duplicates, and whatever is left over in your temporary table should be the data you're looking for.
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LVL 14

Expert Comment

by:psadac
ID: 11764102
try this :

SELECT field, field, field, field
FROM tblcomp AS c INNER JOIN tblinv AS i ON c.compID = i.compID_Inv
WHERE i.mfgID = 56
GROUP BY i.compID_Inv
ORDER BY c.CompanyName;
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LVL 1

Author Comment

by:normenclature
ID: 11764567
thanks!

I decided instead of trying to figure out how to load 4.1 on top of XAMPP, I'd just reconfigure the SQL of the existing.  It really is only about 5 different SQL calls that I have to re-write.  Not a biggie.

I appreciate it--  I figured I'd have to do a temp table, but wasn't sure if there was something out there that someone else knew that I didn't.

thanks again.
0
 

Expert Comment

by:sajithnair
ID: 11980989
This will solve your problem. Please try and let me know.

SELECT c.field, c.field, c.field, c.field FROM tblcomp c, tblinv i WHERE c.compID = i.compID_Inv
AND i.mfgID = 56 ORDER BY c.CompanyName ASC

Regards
Sajith
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