05 - set operators grouping and windows functions

8/20/2019 05 - SET Operators Grouping and Windows Functions

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05 | SET Operators, Windows Functions,

and Grouping


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Querying Microsoft SQL Server 2012 Jump Start

05 | SET Operators, Windows Functions, and Grouping

SET operators, Windows functions, GROUPING sets PIVOT, UNPIVOT, CUBE, ROLLUP)

06 | Modifying DataINSERT, UPDATE, and DELETE statements, use of defaults, constraints, and triggers, OUTPUT

07 | Programming with T-SQLUsing T-SQL programming elements, implementing error handling, understanding and implementing transactions

08 | Retrieving SQL Server Metadata and Improving Query PerformanceQuerying system catalogs and dynamic management views, creating and executing stored procedures, improving SQL

Server query performance


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[ORDER BY ]


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-- only distinct rows from both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailUNIONSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail

Purchasing Sales


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Purchasing Sales

-- all rows from both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailUNION ALLSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail


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Using the INTERSECT operator

Purchasing Sales

INTERSECT

-- only rows that exist in both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailINTERSECTSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail


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Using the EXCEPT operator

Sales Purchasing

-- only rows from Sales are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailEXCEPTSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail


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1.

2.

SELECT FROM AS

CROSS/OUTER APPLY AS


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SELECT CustomerID, OrderDate, TotalDue,SUM(TotalDue) OVER(PARTITION BY CustomerID)

AS TotalDueByCustFROM Sales.SalesOrderHeader;

CustomerID OrderDate TotalDue TotalDueByCust---------- -------------------------- -------- --------------11000 2007-08-01 00:00:00.000 3756.989 9115.1341

11000 2007-10-01 00:00:00.000 2587.8769 9115.134111000 2006-09-01 00:00:00.000 2770.2682 9115.134111001 2007-08-01 00:00:00.000 2674.0227 7054.187511001 2006-11-01 00:00:00.000 3729.364 7054.187511001 2007-04-01 00:00:00.000 650.8008 7054.1875


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Function Description

RANK Returns the rank of each row within the partition of a result

set. May include ties and gaps.DENSE_RANK Returns the rank of each row within the partition of a result

set. May include ties but will not include gaps.

ROW_NUMBER Returns a unique sequential row number within partitionbased on current order.

NTILE Distributes the rows in an ordered partition into a specified

number of groups. Returns the number of the group to whichthe current row belongs.


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Function Description

LAG Returns an expression from a previous row that is a defined offset

from the current row. Returns NULL if no row at specifiedposition.

LEAD Returns an expression from a later row that is a defined offsetfrom the current row. Returns NULL if no row at specifiedposition.

FIRST_VALUE Returns the first value in the current window frame. Requires

window ordering to be meaningful.LAST_VALUE Returns the last value in the current window frame. Requires

window ordering to be meaningful.


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Pivoted data


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1.

2.

3.

SELECT Category, [2006],[2007],[2008]FROM ( SELECT Category, Qty, Orderyear

FROM Sales.CategoryQtyYear) AS DPIVOT(SUM(QTY) FOR orderyearIN([2006],[2007],[2008])) AS pvt;

Grouping

Spreading

Aggregation

SELECT VendorID, [250] AS Emp1, [251] AS Emp2,[256] AS Emp3, [257] AS Emp4, [260] AS Emp5FROM(SELECT PurchaseOrderID, EmployeeID, VendorIDFROM Purchasing.PurchaseOrderHeader) pPIVOT(COUNT (PurchaseOrderID)

FOR EmployeeID IN( [250], [251], [256], [257], [260] )) AS pvtORDER BY pvt.VendorID;

VendorID Emp1 Emp2 Emp3 Emp4 Emp5-------- ----- ----- ----- ----- -----

1492 2 5 4 4 4

1494 2 5 4 5 4

1496 2 4 4 5 5


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CREATE TABLE pvt (VendorID int, Emp1 int, Emp2 int,Emp3 int, Emp4 int, Emp5 int);

GOINSERT INTO pvt VALUES (1,4,3,5,4,4);INSERT INTO pvt VALUES (2,4,1,5,5,5);INSERT INTO pvt VALUES (3,4,3,5,4,4);GO

SELECT VendorID, Employee, OrdersFROM

(SELECT VendorID, Emp1, Emp2, Emp3, Emp4, Emp5FROM pvt) p

UNPIVOT

(Orders FOR Employee IN(Emp1, Emp2, Emp3, Emp4, Emp5)

)AS unpvt;GO VendorID Employee Orders

1 Emp1 4

1 Emp2 3

W iti i ith i t


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Writing queries with grouping sets

SELECT FROM GROUP BYGROUPING SETS(

(),--one or more columns

(),--one or more columns() -- empty parentheses if aggregating all rows

);

SELECT TerritoryID, CustomerID, SUM(TotalDue) ASTotalAmountDue

FROM Sales.SalesOrderHeaderGROUP BYGROUPING SETS((TerritoryID),(CustomerID),());

TerritoryID CustomerID TotalAmountDue

--------------- ----------- --------------NULL 30116 211671.2674NULL 30117 919801.8188NULL 30118 313671.5352NULL NULL 123216786.1159

3 NULL 8913299.24736 NULL 18398929.1889 NULL 11814376.09521 NULL 18061660.3717 NULL 8119749.346

CUBE d ROLLUP


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CUBE and ROLLUP

SELECT TerritoryID, CustomerID, SUM(TotalDue) ASTotalAmountDueFROM Sales.SalesOrderHeaderGROUP BY CUBE(TerritoryID, CustomerID)

ORDER BY TerritoryID, CustomerID;

SELECT TerritoryID, CustomerID, SUM(TotalDue) ASTotalAmountDueFROM Sales.SalesOrderHeaderGROUP BY ROLLUP(TerritoryID, CustomerID)ORDER BY TerritoryID, CustomerID;


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[ORDER BY ]


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-- only distinct rows from both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailUNION

SELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail

-- all rows from both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailUNION ALLSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail

-- only rows that exist in both queries are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailINTERSECTSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail

-- only rows from Sales are returnedSELECT ProductID, OrderQty, UnitPrice FROM Sales.SalesOrderDetailEXCEPTSELECT ProductID, OrderQty, UnitPrice FROM Purchasing.PurchaseOrderDetail


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Pivoting data is rotating data from a rows-based orientation to acolumns-based orientation and DISTINCT values from a single

column are displayed across as column headings - may includeaggregation

The GROUPING SETS clause builds on the T-SQL GROUP BYclause by allowing multiple groups to be defined in the samequery

A CUBE provides a shortcut for defining grouping sets given alist of columns therefore all possible combinations of GROUPINGSETS are created

A ROLLUP provides a shortcut for defining grouping sets, bycreating combinations with the assumption the input columnsform a hierarchy


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Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information

provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, I MPLIED OR STATUTORY, AS TO THE I NFORMATION IN THIS PRESENTATION.

05 - set operators grouping and windows functions

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