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Base de données, Tables, Vues, Index et syntaxe SQL
Hi Jim,
I have tried it without the NOFILTER clause without much change in speed. Removing this clause is sometimes dramatically faster since it uses a filter on an existing base table instead of building a new result set.
As for the Fox and SQL data engines, they are dramatically different, though they generally produce the same results if you use ANSI syntax. What appears to be happening in Fox is that it builds the entire result set and then returns only the top x records. In this case, the entire result set can be over 500MB. SQL is quite a bit faster, it *appears* to determine the top x records prior to writing a result set. In this case, everything it needs to determine the top x records is contained in the index.
Mike
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