Hi all,
Until now I was only using M$ Access databases, but I want to change to
another database for reasons of performance (and to Linux for reasons of
money).
I already exported two Access tables to MySQL.
One is called LinkedInfo: 600.000 records, 8 columns with indexes on
Record_ID and Link_ID.
The other one JoinedLinkedInfo: about 2 million records, 6 columns with
indexes on Link_ID, Field_ID and ValueNum.
When I'm doing the following query:
SELECT SUM(JoinedlinkedInfo.ValueNum) AS Amount, LinkedInfo.Record_ID FROM
(LinkedInfo LEFT JOIN JoinedLinkedInfo ON LinkedInfo.Link_ID =
JoinedLinkedInfo.Link_ID) WHERE (JoinedLinkedInfo.Field_ID=21) GROUP BY
LinkedInfo.Record_ID;
mySQL gives me the result (84.245 records) after... 2 hours and 59 minutes.
The same query (on a similar pc) in Access takes about 6-7 minutes.
What am I doing wrong???
Marc
