Flink SQL:Queries(Set Operations)

Set Operations

Batch Streaming

UNION

UNION and UNION ALL return the rows that are found in either table. UNION takes only distinct rows while UNION ALL does not remove duplicates from the result rows.
UNION和UNION ALL返回在任一表中找到的行。UNION只接受不同的行，而UNION ALL不会从结果行中删除重复项。

Flink SQL> create view t1(s) as values ('c'), ('a'), ('b'), ('b'), ('c');
Flink SQL> create view t2(s) as values ('d'), ('e'), ('a'), ('b'), ('b'