This document provides information about window functions in SQL Server including: - Common window functions like ROW_NUMBER, RANK, DENSE_RANK, FIRST_VALUE, LAST_VALUE, LAG, CUME_DIST, PERCENT_RANK and PERCENTILE_DISC/CONT. - The syntax and usage of each window function including their clauses and arguments. - Examples of queries using some window functions to return the first or last value in a partition, calculate a running total, and return the lagged value from a previous row. The document is a reference for different window functions in SQL Server and how to apply them in queries.

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10. OVER( [ <PARTITION BY clause> ]
[ <ORDER BY clause> ]
[ <ROW or RANGE clause> ] )
• PARTITION BY • ORDER BY • ROWS | RANGE -

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18. LAST_VALUE(scalar_expression)
OVER ([partition_by_clause] order_by_clause)
• scalar_expression –
• OVER –

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20. SELECT OrderID, CustomerID,
FIRST_VALUE(OrderID) OVER(PARTITION BY CustomerID ORDER BY OrderID
ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
AS FirstOrderID
FROM dbo.Orders
WHERE CustomerID IN (1,2)

21. SELECT OrderID, CustomerID,
LAST_VALUE(OrderID) OVER(PARTITION BY CustomerID ORDER BY OrderID
ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)
AS FirstOrderID
FROM dbo.Orders
WHERE CustomerID IN (1,2)

23. SELECT st1.[Date], st1.TicketCount,
RunningTotal = SUM(st2.TicketCount)
FROM dbo.SpeedingTickets AS st1
INNER JOIN dbo.SpeedingTickets AS st2
ON st2.[Date] <= st1.[Date]
GROUP BY st1.[Date], st1.TicketCount
ORDER BY st1.[Date];
From Aaron Bertrand

24. SELECT [Date], TicketCount,
RunningTotal = TicketCount +
COALESCE(( SELECT SUM(TicketCount)
FROM dbo.SpeedingTickets AS s
WHERE s.[Date] < o.[Date]), 0 )
FROM dbo.SpeedingTickets AS o
ORDER BY [Date];

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29. LAG (scalar_expression [,offset] [,default])
OVER ([partition_by_clause] order_by_clause)
• scalar_expression –
• Offset –
• Default –
• OVER –

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33. CUME_DIST ( ) OVER
([ partition_by_clause ] order_by_clause)
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34. PERCENT_RANK ( ) OVER
([ partition_by_clause ] order_by_clause)
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36. PERCENTILE_DISC ( numeric_literal) WITHIN GROUP (
ORDER BY expression) OVER ([<partition_by_clause> ] )
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37. PERCENTILE_CONT ( numeric_literal) WITHIN GROUP (
ORDER BY expression) OVER ([<partition_by_clause> ] )
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40. Deck by Shy Engelberg and Kevin Boles