|Oracle9i SQL Reference
Release 1 (9.0.1)
Part Number A90125-01
Functions, 82 of 166
"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, 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 built-in function expressions for expr, but you cannot nest analytic functions.
"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.