SORT (GROUP BY NOSORT)

Description

Group rows together based on column values. No sort is required

Versions

This operation is implemented in the following versions

Example

This example was developed using Oracle 9.2.0.1 on Windows 2000

This example requires the following table definition

    CREATE TABLE t1 (c1 NUMBER NOT NULL);

    CREATE INDEX i1 ON t1 (c1);

The table does not need to be analysed

The statement

    SELECT /*+ INDEX (t1 i1) */ c1 FROM t1
    GROUP BY c1;

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   SORT (GROUP BY NOSORT)
2   1     INDEX (FULL SCAN) OF 'I1'