SQL语法，用于连接表，同时保留数据来自的表名

有两个表abcd，efgh：-

abcd–ID、销售日期、网站、类型

efgh-ID、salesorderdate、事件、web、mmid

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将它们与表名结合起来，作为其来源的列之一。您可以使用

UNION ALL

执行此任务

SELECT WEB.ID,WEB.RECEIVED_AT_DATE,WEB.BROWSER,NULL AS EVENT_DATE,NULL AS DEVICE_TYPE,WEB.LIBRARY, NULL AS SCREEN_WIDTH,NULL AS SCREEN_HEIGHT, 'WEB' VALUE_FROM_TABLE FROM 
LOGIN_WEB WEB
UNION ALL
SELECT APP.ID,NULL AS RECEIVED_AT_DATE, NULL AS BROWSER,APP.EVENT_DATE,APP.DEVICE_TYPE,APP.LIBRARY,APP.SCREEN_WIDTH, APP.SCREEN_HEIGHT,'APP' VALUE_FROM_TABLE  FROM LOGIN_APP APP

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使用UNION ALL，假设2个表的id列和库列的数据类型分别相同：

select 
id, 
Library, 
Received_at_date, 
Browser, 
null as Event_date, 
null as Device_type, 
null as Screen_width, 
null as Screen_height, 
'Login_web' as value_from_table
from Login_web

UNION ALL

select 
id, 
Library, 
null as Received_at_date, 
null as Browser, 
Event_date, 
Device_type, 
Screen_width, 
Screen_height, 
'Login_app' as value_from_table
from Login_app

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请在您的问题中添加示例数据，并向我们展示预期的输出。这两张桌子是什么关系？@DJKarma，如果你不介意的话，请你也投票支持我的答案好吗？谢谢