HASH JOIN

Description

Perform a hash join between two row sources

Versions

This operation is implemented in the following versions

7.3.4
8.0.4
8.0.5
8.0.6
8.1.5
8.1.6
8.1.7
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 TABLE t2 (c1 NUMBER,c2 NUMBER);

The table does not need to be analysed

The statement

    SELECT /*+ USE_HASH (t1 t2) */ t1.c2,t2.c2
    FROM t1,t2
    WHERE t1.c1 = t2.c1

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   HASH JOIN
2   1     TABLE ACCESS (FULL) OF 'T1'
3   1     TABLE ACCESS (FULL) OF 'T2'