Oracle® Database SQL Language Reference 11g Release 2 (11.2) Part Number E1711803 


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Syntax
See Also:
"Analytic Functions" for information on syntax, semantics, and restrictions, including valid forms ofexpr
Purpose
NTILE
is an analytic function. It divides an ordered data set into a number of buckets indicated by expr
and assigns the appropriate bucket number to each row. The buckets are numbered 1 through expr
. The expr
value must resolve to a positive constant for each partition. Oracle Database expects an integer, and if expr
is a noninteger constant, then Oracle truncates the value to an integer. The return value is NUMBER
.
The number of rows in the buckets can differ by at most 1. The remainder values (the remainder of number of rows divided by buckets) are distributed one for each bucket, starting with bucket 1.
If expr
is greater than the number of rows, then a number of buckets equal to the number of rows will be filled, and the remaining buckets will be empty.
You cannot nest analytic functions by using NTILE
or any other analytic function for expr
. However, you can use other builtin function expressions for expr
.
See Also:
"About SQL Expressions" for information on valid forms ofexpr
and Table 310, "Implicit Type Conversion Matrix" for more information on implicit conversionExamples
The following example divides into 4 buckets the values in the salary
column of the oe.employees
table from Department 100. The salary
column has 6 values in this department, so the two extra values (the remainder of 6 / 4) are allocated to buckets 1 and 2, which therefore have one more value than buckets 3 or 4.
SELECT last_name, salary, NTILE(4) OVER (ORDER BY salary DESC) AS quartile FROM employees WHERE department_id = 100 ORDER BY last_name, salary, quartile; LAST_NAME SALARY QUARTILE    Chen 8200 2 Faviet 9000 1 Greenberg 12008 1 Popp 6900 4 Sciarra 7700 3 Urman 7800 2