database indexes

[LordRogaine]

Can anyone recommend some reading material about indexing databases. I would like to know if it matters if a tabe has it's field's index as the first few columns or is an index just as efficient if one of the last columns in indexed. thanks in advance Lord rogaine

[NogDog]

Generally speaking, you want indexes on columns which are used within WHERE clauses, and you do not want indexes on any columns which are not. Indexing a column used in a WHERE clause speeds up the selection process, but indexing columns which do not need indexing can slow down queries (especially inserts and updates).