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From:mathias fatene Date:April 25 2005 8:24pm
Subject:RE: Query question
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Hi,
Im sorry to disappoint you but this is an anti-performance solution.
Use joins rathers than subqueries, and don't use joins if you can (all
data in the mother table).
 
Imagine that table2 has 30.000.000 records, and not good indexes. you
can wait for your answer a long time.
 
Best Regards
--------------------
Mathias FATENE
 
Hope that helps
*This not an official mysql support answer
 

-----Original Message-----
From: Peter Brawley [mailto:peter.brawley@stripped] 
Sent: lundi 25 avril 2005 22:17
To: Jeff McKeon
Cc: mysql@stripped
Subject: Re: Query question


Jeff,

Then do it with 2 queries,

SELECT @d := MAX( datestamp )

FROM table2

WHERE parentID = X;


SELECT *
FROM table2
WHERE parentID = X AND datestamp=@d;

PB

-----

Jeff McKeon wrote: 

Thanks all but I don't have a mysql version high enough for subqueries.



Thanks,



Jeff



  

-----Original Message-----

From: Peter Brawley [mailto:peter.brawley@stripped] 

Sent: Monday, April 25, 2005 4:01 PM

To: Jeff McKeon

Cc: mysql@stripped

Subject: Re: Query question





Jeff,



Something like ...



SELECT *

FROM table2 AS a

WHERE datestamp = (

  SELECT MAX( b.datestamp )

  FROM table2 AS b

  WHERE a.parentID = b.parentID

);



PB



-----





Jeff McKeon wrote:



    

I have a table that contains records that link back to a 

      

main talbe in 

    

a many to one configuration linked by table1.id = table2.parentid



Table1 (one)

Table2 (many)



I want to pull the latest records from table2 for each 

      

record in table1 

    

where certain criteria applie.



So, if record 100 in table1 links to 5 corresponding records 

      

in table2, 

    

I want to pull the latest record from table2 where table2.parentid = 

100 and table2.user not like 'john'



There is a datestamp field in table2.



I just can't figure out how to do this.



Thanks,



Jeff





 



      

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Thread
Query questionJeff McKeon25 Apr
  • Re: Query questionSGreen25 Apr
  • RE: Query questionmathias fatene25 Apr
    • RE: Query questionSGreen25 Apr
      • RE: Query questionmathias fatene25 Apr
  • Re: Query questionPeter Brawley25 Apr
    • RE: Query questionmathias fatene25 Apr
RE: Query questionJeff McKeon25 Apr
  • Re: Query questionPeter Brawley25 Apr
    • RE: Query questionmathias fatene25 Apr
      • Re: Query questionPeter Brawley25 Apr
      • RE: Query questionSGreen25 Apr
        • RE: Query questionmathias fatene26 Apr
          • Re: Query questionMartijn Tonies26 Apr
            • RE: Query questionmathias fatene26 Apr
              • Re: Query questionChris Ramsay26 Apr
                • Re: Query questionmfatene26 Apr
  • Re: Query questionPeter Brawley25 Apr
  • RE: Query questionSGreen25 Apr
RE: Query questionJeff McKeon25 Apr
  • Re: Query questionPeter Brawley25 Apr
RE: Query questionJeff McKeon25 Apr
  • Re: Query questionPeter Brawley25 Apr
RE: Query questionJeff McKeon25 Apr