Re: Partitioning not working need primary key?

[newbie Shai]

Dear Rick,
This is interesting to me.

If you have an index (or the PK) with (outletID,receiptID,dateTime) and you say
WHERE outletID = 123 AND dateTime >=...
It will use that index starting with outletID

If you have an index (or the PK) with (outletID,receiptID,dateTime) and you say
WHERE receiptID = 987 AND dateTime >=...
It will ignore that index, and would use your proposed INDEX(dateTime) if it existed.


I dont quite understand why the second query will not be using the composite index whereas the first will as the second one too have part of the composite index rite?