Question

I have a logfile which logs the insert/delete/updates from all kinds of tables.
I would like to get an overview of for example the last 20 people which records where updated, ordered by the last update datetime DESC

What I have now is:

SELECT DISTINCT logfile.idvalue, DATE_FORMAT(logfile.logDateTime,'%d-%m-%Y  %H:%i') AS thedatetime, CONCAT_WS(' ',people.peopleSurname,people.peopleLastname) AS peopleName
FROM logfile,people
WHERE 0=0
AND logfile.tablename='people'
AND logfile.action='update'
AND logfile.idvalue=people.peopleID
GROUP BY logfile.idvalue
ORDER BY logfile.logDateTime DESC,logfile.idvalue DESC

But this results in logDateTimes which don’t correspond to the datetime of the latest (Max) “update-entry”
What am i missing?!

thanks
Bart

Answer 1

SELECT  *
FROM    logfile lf
WHERE   tablename = 'people'
        AND action = 'update'
        AND logdatetime = 
        (
        SELECT  MAX(logdatetime)
        FROM    logfile lfi
        WHERE   lfi.idvalue = lf.idvalue
                AND lfi.tablename = lf.tablename
                AND lfi.action = lf.action
        )
ORDER BY
        logdatetime DESC
LIMIT 20

Create the following indexes:

(tablename, action, idvalue, logdatetime)
(tablename, action, logdatetime)

for this to work fast.