我如何在SQL查询中设置标志

Question

我的查询：

CREATE OR REPLACE VIEW Basic
AS
SELECT id FROM my_post
UNION
SELECT id FROM scrap_post

如果该行来自my_post，那么我想设置标记p，否则设置s。

Answer 1

添加硬编码值

CREATE OR REPLACE VIEW Basic
AS
select id,'p' as flag from my_post
UNION 
select id,'s' from scrap_post

注意：如果您不关心结果中的重复项，请将UNION更改为运行速度更快的UNION ALL