Oracle9i SQL Reference Release 2 (9.2) Part Number A9654001 

Functions, 84 of 177
ntile::=
See Also:
"Analytic Functions" for information on syntax, semantics, and restrictions 
NTILE
is an analytic function. It divides an ordered dataset into a number of buckets indicated by expr
and assigns the appropriate bucket number to each row. The buckets are numbered 1 through expr,
and expr
must resolve to a positive constant for each partition.
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 use NTILE
or any other analytic function for expr
. That is, you can use other builtin function expressions for expr
, but you cannot nest analytic functions.
See Also:
"About SQL Expressions" for information on valid forms of 
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; LAST_NAME SALARY QUARTILE    Greenberg 12000 1 Faviet 9000 1 Chen 8200 2 Urman 7800 2 Sciarra 7700 3 Popp 6900 4

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