indexing - Is there any harm in creating a index that is a subset of unique clustered index? -

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i have table abc , unique clustered index on below columns

col1, col2, col4, col5, col6

it's vast table , analyzing of queries on table feel new index of below columns help.

col1, col5, col2

but, not sure of performance impact , need know whether it;s idea create additional index. so, can have index has columns subset of unique clustered index (also order changed)?

haven't found related while searching internet. hint's/thoughts helpful.

as indexes computational used rapidly access data, can have several indexes overlaps without problems reading data. solution of index (col1, col5, col2) 1 index , (col1, col2, col4, col5, col6) usable , not deal performance issue reading data.

of course, index comes cost when adding data (must write index), if table have big amount of write, have loss of time when writing data.


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