My experience has been that PIVOT and Agg(CASE. These may or may not lead to worse performance compared with CASE, depending on various factors including the skill level of the implementor.Įxamples of these problematic cases are covered in Itzik's article, and also well explained in Robert Sheldon's Simple Talk article, Questions About Pivoting Data in SQL Server You Were Too Shy to Ask. The main benefit in the PIVOT operator at the moment is that it’s less verbose.įor more advanced pivoting requirements that the (non-standard) PIVOT syntax does not directly support, workarounds are needed. With this in mind, you shouldn’t expect the solution that’s based on the PIVOT operator to perform better than the standard solution. As you can see, this plan is very similar to that of the standard solution-so much so that if you look at the properties of the Aggregate operator, under Defined Values, you’ll find that SQL Server constructed CASE expressions behind the scenes:
#Sql server pivot pro
As Itzik Ben-Gan notes in his SQL Server Pro article, Pivoting Data when looking at the plan for a PIVOT query (emphasis added):įigure 3 shows the plan for the PIVOT query. That is odd, I had kind of expected to see different IO stats, even though I've never looked at them for this particular example.Īre there examples where PIVOT is slower? The IO stats, like the query plan, is identical between the two. PIVOT is a little better, but percentage-wise it doesn't have the same edge as on the first server. Can't reproduce on a second server, but that one is considerably better it's 5 seconds each there with minor variations. If I run them both from a cold cache they both take longer, but PIVOT is still faster, 12 vs 17 seconds. I've tried running them back and forth, it doesn't matter the order they are run in.
![sql server pivot sql server pivot](https://i.stack.imgur.com/6VJfe.png)
Yet SUM(CASE) never comes back in less than 13 seconds, and PIVOT never comes back in over 11 seconds. PIVOT converted to SUM(CASE) in the query analyzer. The plans are the same, 50% of total each. Clearly it must be doing something different under the covers. In my work example, the PIVOT comes back in 10 seconds while the SUM(CASE) comes back in 14. But the SUM(CASE) performs the same drawing from the CTE. In the PIVOT example it is drawing from a CTE whereas the SUM(CASE) is drawing directly from the table. I can't give the DDL because it is an example from my work. Are there examples where PIVOT is slower? PIVOT (SUM(UnitPrice) FOR RateItemTypeID IN (,, )) PVT)Īcross SQL Server 2005, 2008 R2, 20 (the versions of SQL Server I've worked with that implement PIVOT), in my experience, it has always been faster than SUM(CASE) or in a few cases equally fast.
![sql server pivot sql server pivot](https://i.stack.imgur.com/N4ByO.png)
Later, when 2005 introduced PIVOT it became this: SELECT RateID,, , įROM PertinentRates - PertinentRates is a CTE with WHERE clause applied SUM(CASE WHEN RateItemTypeID = 3 THEN UnitPrice ELSE 0 END) SUM(CASE WHEN RateItemTypeID = 2 THEN UnitPrice ELSE 0 END), SUM(CASE WHEN RateItemTypeID = 1 THEN UnitPrice ELSE 0 END), Before SQL Server 2005, when PIVOT was introduced, most people did this: SELECT RateID * UNCOMMENT TO SEE THE DYNAMICALLY CREATED SQL STATEMENT */ĮXEC sp_executesql VIEW PIVOTED TABLE RESULTS */īig shoutout to StackOverflow for help with this example.There are two types of ways to perform a PIVOT. SELECT the dynamic query with all the values for * UNCOMMENT TO SEE THE NEW COLUMN NAMES THAT WILL BE CREATED */ This parameter will hold the Pivoted Column valuesĭECLARE AS NVARCHAR ( MAX ) SELECT = COALESCE + ',', '' ) + QUOTENAME ( ) FROM. This parameter will hold the dynamically created SQL script IF OBJECT_ID ('tempdb.#TBL_TEMP' ) IS NOT NULL DROP TABLE #TBL_TEMP
#Sql server pivot code
Make sure you watch the video but here is the code used in the example. Notice how the city values are now column heads and the respective Average Rent values are underneath. The City values in the City column will become individual columns in a new pivoted dataset with their respective Average Rent values appearing underneath. We’ll use some of these functions to turn the following data set that displays average rents in major American cities into a pivoted denormalized dataset. T-SQL is Microsoft’s SQL language that contains additional functions and capabilities over and above ANSI standards.
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This is not a beginner video as I assume you are familiar with basic SQL concepts.
![sql server pivot sql server pivot](https://1.bp.blogspot.com/-oQ5wLrtXIUg/YAasViaCVGI/AAAAAAAAA9Q/bzt40BqyH2EL94spp2RaboUBPin1eSO_wCLcBGAsYHQ/s349/sql-server-dynamic-pivot-codingvila.png)
In this video I am using SQL Server Express to turn a simple normalized dataset into a pivoted dataset. If you can’t leverage SQL and you work with data, your life will be more difficult than it needs to be. SQL is the lifeblood of any data professional.
#Sql server pivot how to
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