Hello!

Simon Green wrote:

>What I am trying to do in MySQL.
>
>Table1
>
>UserID ProductID       Old_UserID
>1      2               4
>2      3               5       
>
>Table2
>UserID ProductID
>4      Null
>5      Null
>
>Table1 has new correct data. 
>Table2 has old incorrect data.
>The link is Table2.UserID and Old_UserID
>
>What I need to do is update Table 2 with the new data from Table 1,
>But I can not get this to work..e.g.
>
>UPDATE Table2.ProductID
>SET Table2.ProductID = Table1.ProductID
>WHERE Table1.Old_UserID = Table2.UserID
>
>REPLACE will not work as these are not KEY fields.
>Once I have done the ProductID I should then be able to do the UserID using
>the ProductID (as all values in one table are unique).
>  
>

SELECT
    concat('UPDATE Table2 SET ProductID = ',
        t1.ProductID,
        ' WHERE UserID = ',
        t1.UserID,
        ';'
    )
INTO OUTFILE
    '/tmp/update.sql'
FROM
    Table1 t1
    LEFT JOIN Table2 t2 ON (t1.Old_UserID = t2.UserID)
WHERE
    t2.UserID IS NOT NULL
;

\. /tmp/update.sql

This might help...but better take a look at /tmp/update.sql, before 
executing it!!!

Greetings
 Ralf

-- 
Ralf Narozny
SPLENDID Internet GmbH & Co KG
Skandinaviendamm 212, 24109 Kiel, Germany
fon: +49 431 660 97 0, fax: +49 431 660 97 20
mailto:[EMAIL PROTECTED], http://www.splendid.de




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