UNION ALL语句将两个流式数据合并。两个流式数据的字段完全一致,包括字段类型和字段顺序。
语法
select_statement
UNION ALL
select_statement;
示例
- 测试数据
表1:test_source_union1
a(varchar) b(bigint) c(bigint) test1 1 10 表2:test_source_union2a(varchar) b(bigint) c(bigint) test1 1 10 test2 2 20 表3:test_source_union3a(varchar) b(bigint) c(bigint) test1 1 10 test2 2 20 test1 1 10 - 测试语句
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;
- 测试结果
d(varchar) e(bigint) f(bigint) test1 1 10 test2 2 20 test1 2 20 test1 3 30 test2 4 40 test1 4 40