UNION-ALL

Description

Performs a union all set operation between two tables. Duplicate rows are not removed

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);
    CREATE TABLE t2 (c1 NUMBER);

The table does not need to be analysed

The statement

    SELECT c1 FROM t1
    UNION ALL
    SELECT c1 FROM t2;

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   UNION-ALL
2   1     TABLE ACCESS (FULL) OF 'T1'
3   1     TABLE ACCESS (FULL) OF 'T2'