Walter Meester
HoogkarspelNetherlands
General information
Category:
Databases,Tables, Views, Indexing and SQL syntax
Hi kevin,
>I have a table - field2 is indexed, field1 isn't. Does it matter which order I put the WHERE clause in when using 2 fields. ie:
>
>SELECT * FROM myTable;
> WHERE field1 = "M";
> AND field2 = "KLAWRENCE"
>
>How will SQL handle this, will it use the indexed field to optimize the SELECT or will it handle the first expression first, then check the 2nd field?
It will first process the expressions that can be optimized (field2 = "KLAWRENCE") by its index then it will retrieve the actual records from the disk and filter with the non-optimizable expressions (field1 = "M")
Walter,
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