partition by sql server
-- When using an aggregation function (SUM, COUNT, RANK, etc...) -- Creates a specification on which you need to perform that agreggation -- Example: SELECT Customercity, SUM(Orderamount) OVER(PARTITION BY Customercity) AS SumOrderAmount -- performs avg amount when and only when you see a customer city -- Orderamount | Customercity --(Comment added)-- | SumOrderAmount -- 100 | Chicago "partition1" | 250 -- 150 | Chigago "partition1" | 250 -- 50 | Houston "partition2" | 75 -- 25 | Houston "partition2" | 75
