Oracle PL/SQL Tutorial/Analytical Functions/PERCENTILE DISC

PERCENTILE_DISC(x) examines the cumulative distribution values in each group until it finds one that is greater than or equal to x

PERCENTILE_DISC(x) operate in the reverse sense of CUME_DIST()

This function takes a probability value (between 0 and 1) and returns an approximate percentile value (for a discrete distribution).

The general format for this function is:

PERCENTILE_DISC (expr) WITHIN GROUP (ORDER BY expr [DESC | ASC]) OVER (query_partition_clause)]

SQL> -- create demo table
SQL> create table myTable(
  2    id           NUMBER(2),
  3    value        NUMBER(6,2)
  4  )
  5  /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into myTable(ID,  value)values (1,9);
1 row created.
SQL> insert into myTable(ID,  value)values (2,2.11);
1 row created.
SQL> insert into myTable(ID,  value)values (3,3.44);
1 row created.
SQL> insert into myTable(ID,  value)values (4,-4.21);
1 row created.
SQL> insert into myTable(ID,  value)values (5,10);
1 row created.
SQL> insert into myTable(ID,  value)values (6,3);
1 row created.
SQL> insert into myTable(ID,  value)values (7,-5.88);
1 row created.
SQL> insert into myTable(ID,  value)values (8,123.45);
1 row created.
SQL> insert into myTable(ID,  value)values (9,98.23);
1 row created.
SQL> insert into myTable(ID,  value)values (10,938.23);
1 row created.
SQL> insert into myTable(ID,  value)values (11,984.23);
1 row created.
SQL> insert into myTable(ID,  value)values (12,198.23);
1 row created.
SQL> insert into myTable(ID,  value)values (13,928.87);
1 row created.
SQL> insert into myTable(ID,  value)values (14,25.37);
1 row created.
SQL> insert into myTable(ID,  value)values (15,918.3);
1 row created.
SQL> insert into myTable(ID,  value)values (16,9.23);
1 row created.
SQL> insert into myTable(ID,  value)values (17,8.23);
1 row created.
SQL>
SQL> select * from myTable
  2  /
        ID      VALUE
---------- ----------
         1          9
         2       2.11
         3       3.44
         4      -4.21
         5         10
         6          3
         7      -5.88
         8     123.45
         9      98.23
        10     938.23
        11     984.23
        ID      VALUE
---------- ----------
        12     198.23
        13     928.87
        14      25.37
        15      918.3
        16       9.23
        17       8.23
17 rows selected.
SQL>
SQL>
SQL>
SQL> SELECT PERCENTILE_DISC (0.2) WITHIN GROUP (ORDER BY id )
  2  from myTable;
PERCENTILE_DISC(0.2)WITHINGROUP(ORDERBYID)
------------------------------------------
                                         4
SQL>
SQL>
SQL> -- clean the table
SQL> drop table myTable
  2  /
Table dropped.
SQL>