MySQL将表名作为结果集的一部分

Question

我有多个具有相同结构的表，用于存储文本短语。例如：

TABLE_1

id | text
1. | Hello

TABLE_2。

id | text
1. | Goodbye

TABLE_3。

id | text
1. | Hello

我希望看到包含文字的所有表格＆＃39; Hello＆＃39;所以我的查询很简单：

SELECT * FROM table_1, table_2, table_3 WHERE text ='Hello'

这告诉我是否＆＃39;你好＆＃39;存在但不存在。结果是：

id | text
1. | Hello
1. | Hello

有没有办法将表名放入结果集中，以便结果集看起来像这样？

id | text  | table_name
1. | Hello | table_1
1. | Hello | table_3

提前致谢。

Answer 1

SELECT *, 'table_1' as tablename FROM table_1 WHERE text ='Hello'
union all
SELECT *, 'table_2' as tablename FROM table_2 WHERE text ='Hello'
union all
SELECT *, 'table_3' as tablename FROM table_3 WHERE text ='Hello'

Answer 2

试试这个

SELECT id, text, 'table_1' as tablename FROM table_1 WHERE text ='Hello'
union all
SELECT id, text, 'table_2' as tablename FROM table_2 WHERE text ='Hello'
union all
SELECT id, text, 'table_3' as tablename FROM table_3 WHERE text ='Hello'

Answer 3

您想要的查询是union all，而不是cross join（您在from子句中使用逗号得到的内容）：

(select 'table_1' as which, t1.* from table_1 t1 where text ='Hello')
union all
(select 'table_2' as which, t2.* from table_2 t2 where text ='Hello')
union all
(select 'table_3' as which, t3.* from table_3 t3 where text ='Hello')