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PERCENT_RANK (aggregate)

The PERCENT_RANK function returns the relative percentile rank of a row that is hypothetically inserted into a group of rows.

FL 504

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Passthrough-only expression: This function is passthrough-only and cannot run on Db2 for z/OS® without acceleration. For information about invoking this function, see Accelerating queries with passthrough-only expressions.
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Read syntax diagramSkip visual syntax diagram PERCENT_RANK ( ,expression ) WITHIN GROUP ( order-by-clause )
order-by-clause
Read syntax diagramSkip visual syntax diagram ORDER BY ,sort-keyasc-optiondesc-option
asc-option
Read syntax diagramSkip visual syntax diagram ASC NULLS LASTNULLS FIRST
desc-option
Read syntax diagramSkip visual syntax diagram DESC NULLS FIRSTNULLS LAST

The schema is SYSIBM.

expression
An expression that specifies a row that is hypothetically inserted into a group of rows. The expression must return a value that is a built-in data type. The expression must be a constant, a variable, or a cast of a constant or variable.
order-by-clause
ORDER BY
Specifies the order of the rows from the same grouping set that are processed in the aggregation.
sort-key
The sort key can be a column name or a sort-key-expression. If the sort key is a constant, it does not refer to the position of the output column. A constant implies no sort key, unlike a constant in the ordinary ORDER BY clause.
ASC
Uses the values of the sort-key in ascending order.
DESC
Uses the values of the sort-key in descending order.
NULLS FIRST
The ordering considers null values before all non-null values in the sort order.
NULLS LAST
The ordering considers null values after all non-null values in the sort order.

The number of expressions must be the same as the number of sort-key expressions. The data type of each expression and the data type of the corresponding sort-key expression must be compatible.

The data type of the result is DECFLOAT(34). The actual result is greater than 0.0 and less than or equal to 1.0.

Example

Set the host variable PR to the relative percentile rank of a hypothetical new employee's salary of 47000 within the salaries of the employees in department 'A00'.
   SELECT PERCENT_RANK(47000) WITHIN GROUP (ORDER BY SALARY) 
      INTO :PR FROM EMPLOYEE WHERE WORKDEPT = 'A00'
PR is set to a value of 0.4.
The following result set is shown for reference.
   SELECT SALARY FROM EMPLOYEE WHERE WORKDEPT = 'A00' ORDER BY SALARY

SALARY     
-----------
   39250.00
   46500.00
   49250.00
   66500.00
  152750.00

  5 record(s) selected.
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