The UNION ALL clause is used to combine two streaming data sets. The field types and sequences of the two streaming data sets must be the same.

Syntax

select_statement
UNION ALL
select_statement;

Example

  • Test data
    Table 1: test_source_union1
    a (VARCHAR) b (BIGINT) c (BIGINT)
    test1 1 10
    Table 2: test_source_union2
    a (VARCHAR) b (BIGINT) c (BIGINT)
    test1 1 10
    test2 2 20
    Table 3: test_source_union3
    a (VARCHAR) b (BIGINT) c (BIGINT)
    test1 1 10
    test2 2 20
    test1 1 10
  • Statement 
    SELECT
    a,
    sum(b),
    sum(c)
FROM 
    (SELECT * from test_source_union1
    UNION ALL
    SELECT * from test_source_union2
    UNION ALL
    SELECT * from test_source_union3
    )t
 GROUP BY a;
  • Result
    d (VARCHAR) e (BIGINT) f (BIGINT)
    test1 1 10
    test2 2 20
    test1 2 20
    test1 3 30
    test2 4 40
    test1 4 40