如何表示某行来自哪个表? [英] How to signify which table a certain row comes from?

问题描述

说我正在从一个SQL查询中的三个唯一表中提取列.并说这些列具有相同的数据类型.有没有一种方法可以在我的结果中增加一个额外的列，以表示某行来自哪个表?就像table_A的1，table_B的2，等等.我该怎么做?

Say I was pulling columns from three unique tables in a sql query. And say those columns have the same datatype. Is there a way I could have an extra column in my results that would signify which table a certain row came from? Like 1 for table_A, 2 from table_B, etc. How would I do that?

推荐答案

SELECT "table1" which, colX the_col
FROM table1
WHERE ...
UNION
SELECT "table2" which, colY the_col
FROM table2
WHERE ...
...

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