sql - 联合查询中虚拟列的 where 函数

Question

我是 sql 新手，需要一点帮助。我有union3 个表的查询。我有一个虚拟列，所以我可以知道每行来自哪个表。我希望能够过滤此虚拟列以仅显示特定表中的行。

我正在使用 Microsoft Access，这是我目前所拥有的：

SELECT Table1 as Table_Name, Table1.1  
FROM Table1  
UNION ALL  
SELECT Table2 as Table_Name, Table2.1  
FROM Table2  
UNION ALL  
SELECT Table3 as Table_Name, Table3.1  
FROM Table3  
UNION ALL  
WHERE Table_Name = Form1.TextBox  
ORDER BY Table1.1;

我正在尝试将其链接到表单上的列表框，然后有一些文本框来过滤结果。

Answer 1

怎么样：

SELECT * FROM
( SELECT Table1 as Table_Name, Table1.1
FROM Table1
UNION ALL
SELECT Table2 as Table_Name, Table2.1
FROM Table2
UNION ALL
SELECT Table3 as Table_Name, Table3.1
FROM Table3 ) q
WHERE Table_Name = Forms!Form1!TextBox
ORDER BY Table1.1;

见：http ://access.mvps.org/access/forms/frm0031.htm