Mailing List
Home
MySQL General - General MySQL discussion
MaxDB - Everything about MaxDB, formerly known as SAP DB
MySQL on Win32 - Runing MySQL on Windows 9x/Me/NT/2000/XP
Java Help - Mostly related to the MySQL Connector/J driver
ODBC - ODBC with the MySQL Connector/ODBC driver
Perl - Perl support for MySQL with DBI and DBD::mysql
MySQL++ - Programming with the C++ API to MySQL
Subjects
• mysql openssl Question
• mysql:it 's a db not a dbms how it 's possible?!
• Does the binary log enabling affect the MySQL performances?
• Strange behavior, Table Level Permission
• FULLTEXT query format question
• Preventing Duplicate Entries
• Comparing and writing out BLOBS
• Executing MySQL Commands From Within C Program
• Can 't access mysql after kernel upgrade
• Mysql 4 0 Oracle Stored Procedure Trigger Conversion
• Downgrade Mysql from 4 to 3 23
• MySQL Cluster Software
• mysql test 4 1 fails with the gis test
• ERROR 2002: Can 't connect to local MySQL server through socket
• Getting Identity after INSERT
• Update one field with more fields from another table
• ERROR 1045: Access denied for user: 'root@localhost ' (Using
password: NO)
• mysql have same function mthod as Oracle decode()
 
Search:  
Power your search with and, or, +, -, or "some phrase" operators.
AW: Problem selecting from 3 tables

AW: Problem selecting from 3 tables

2004-03-13       - By B. Fongo

 Back

This query work ok. Any suggestion on how to further optimize it?

SELECT PictureName, ProdName, Description, SalesPrice FROM Products
INNER JOIN ProdCategory ON Products.CategoryNr
INNER JOIN ProductsPics on Products.ProdNr
WHERE Products.CategoryNr = ProdCategory.CategoryNr
AND Products.ProdNr = ProductsPics.ProdNr
AND ProdCategory.Category = "$category ";


Peter Brawley?s example below, did not work. I know it is due the fact
that, I forget to mention the structure (relation) between my tables.

So now here you?re:

ProductsPics Products Category
========== ======= =======
ProdNr ProdNr CategoryNr
CategoryNr Category
etc. etc. etc.

-- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
-- ---- ---- ----


-- --Ursprščngliche Nachricht-- --
Von: Peter Brawley [mailto:peter.brawley@(protected)]
Gesendet: Samstag, 13. M?rz 2004 06:40
An: B. Fongo; Mysql@(protected) Mysql. Com
Betreff: Re: Problem selecting from 3 tables

>I 'm having trouble with sql statement to select from 3 tables.
>The first column is in ProductsPics and the rest in Products.

>(qq{SELECT PictureName, ProdName, Description, SalesPrice FROM Products
>INNER JOIN
> ProdCategory USING(CategoryNr) INNER JOIN ProductsPics
>USING(ProdNr) WHERE Products.CategoryNr
> = ProdCategory.CategoryNr AND Products.ProdNr =
>ProductsPics.ProdNr
> AND ProdCategory.Category = "$category "});

No need to write the join conditions twice in the query. Is this what
you want...

SELECT PictureName, ProdName, Description, SalesPrice
FROM Products
INNER JOIN ProdCategory USING(CategoryNr)
INNER JOIN ProductsPics USING(ProdNr)
WHERE ProdCategory.Category = $category;

ie only rows with matches across the 3 tables, scoped by $category?

PB