SQL PERCENT_RANK Function

Calculate the relative rank of each product price.

SELECT ProductName, UnitPrice,
       PERCENT_RANK() OVER(ORDER BY UnitPrice) AS 'Percent Rank'
  FROM Product
 ORDER BY UnitPrice

ProductName	UnitPrice	Percent Rank
Geitost	2.50	0
Guaraná Fantástica	4.50	0.012987012987013
Konbu	6.00	0.025974025974026
Filo Mix	7.00	0.038961038961039
Sir Rodney's Marmalade	81.00	0.961038961038961
Mishi Kobe Niku	97.00	0.974025974025974
Thüringer Rostbratwurst	123.79	0.987012987012987
Côte de Blaye	263.50	1

The percent rank starts at 0 and goes up to 1 (the last row).

Syntax of the PERCENT_RANK function.

PERCENT_RANK() 
  OVER( PARTITION BY expression, ... 
        ORDER BY expression, ... )

SELECT MONTH(OrderDate) AS Month, 
       CONCAT(FirstName, ' ', LastName) AS Customer, TotalAmount, 
       PERCENT_RANK() OVER(PARTITION BY MONTH(OrderDate)
                        ORDER BY TotalAmount) AS 'Percent Rank'
  FROM [Order] O
  JOIN Customer C ON O.CustomerId = C.Id
 WHERE YEAR(OrderDate) = 2013
 ORDER BY MONTH(OrderDate), TotalAmount

Order Month	Customer	TotalAmount	Percent Rank
1	Paolo Accorti	49.80	0
1	Yoshi Latimer	102.40	0.03125
1	Maurizio Moroni	192.00	0.03125
1	Roland Mendel	5796.00	0.9375
1	Jytte Petersen	11283.20	0.96875
1	Jean Fresnière	11493.20	1
2, 3, 4, ... 11
12	Patricio Simpson	12.50	0
12	Paolo Accorti	18.40	0.0212765957446809
12	Pascale Cartrain	28.00	0.0425531914893617
12	Martín Sommer	4035.80	0.957446808510638
12	Marias Larsson	4337.00	0.978723404255319
12	Roland Mendel	6984.50	1

SELECT MONTH(OrderDate) AS 'Month', 
       SUM(TotalAmount) AS 'Monthly Sales', 
       PERCENT_RANK() OVER(ORDER BY SUM(TotalAmount)) 
                        AS 'Sales Distribution'
  FROM [Order]
 WHERE YEAR(OrderDate) = 2013
 GROUP BY MONTH(OrderDate)
 ORDER BY MONTH(OrderDate)

50% of the sales from year 2013 are greater than 50,000.

• Our Sql Window Functions Reference
• Our Sql CUME_DIST Function Reference
• Our Sql JOIN Tutorial