Does Query Speed Depend on Order of WHERE Clause (1 Viewer)

[SmallTime]

Just writing some queries for 500K + records with a various restrictions in the WHERE clause and was wondering if the order in which I restricted the data would have any affect on query performance. Is it better to place the broadest restriction first and then filter down form there or does it not make any significant difference?

 

[MarkK]

I think the biggest impact on performance will be if you apply constraints to fields that are indexed.

 

[SmallTime]

Many thanks for that, I always thought the opposite was true, but will have a quick read-up in the morning.

Ta

 

[spikepl]

I suspect MarkK meant what you thought, i.e. applying indexing to fields with constraints

But google access query optimise There are many other aspects though perhaps of lesser significance.

 

[SmallTime]

Ah ha, reading it again I see that's exactly what Mark meant.

Sorry combinations of late night and square eyes.

Thanks