INDEX (SKIP SCAN DESCENDING)

Description

Perform a descending index skip scan

Versions

This operation was introduced in Oracle 9.0.1

This operation is implemented in the following versions

9.0.1
9.2.0
10.1.0
10.2.0

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,c2 NUMBER);

    CREATE INDEX i1 ON t1 (c1,c2);

Unlike INDEX (SKIP SCAN), the table must be analysed

    ANALYZE TABLE t1 COMPUTE STATISTICS;

The statement

    SELECT /*+ INDEX_SS_DESC (t1 i1) */ c1
    FROM t1
    WHERE c2 = 0;

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   INDEX (SKIP SCAN DESCENDING) OF 'I1' (NON-UNIQUE)