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From:Christian Mack Date:April 16 1999 9:59am
Subject:Re: Select limit question
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Shane Wegner wrote:
> 
> Hi,
> 
> I am trying to write a routine to calculate an average based on the 5
> entries before a certain entry in a table based on the _date column.
> 
> Is this possible with a select statement?  The limit keyword has an offset
> and a limit but can you tell select to return the 5 entries before a
> certain entry.
> 
> Example:
> create table chart(
> _date date,
> symbol varchar(10),
> close double(22,3),
> 5avg double(22,3);
> 
> 5avg should be the last 5 closing values for a symbol.  Any ideas on how
> to do this most efficiently with MySQL would be greatly appreciated.
> Please cc me on replies.
> 
> Thanks in advance,
> Shane
> 
> --
> Shane Wegner: shane@stripped

Hi Shane

With certainEntry_date set to the _date value from the one you search the last 5 closing
values, you can use this:
SELECT * FROM chart WHERE _date < certainEntry_date ORDER BY _date DESC LIMIT 5;

Tschau
Christian

Thread
Select limit questionShane Wegner16 Apr
  • Re: Select limit questionChristian Mack16 Apr