SQL db查詢：如何添加新欄位並分配值

我有 3 個表格，如下面的螢幕截圖所示。我使用 UNION 創建了一個查詢，如下所示。

SELECT T1_ID AS ID, T1_NAME AS NAME, T1_ADD AS ADDRESS
FROM Table1
UNION
SELECT T2_ID AS ID, T2_NAME AS NAME, T2_ADD AS ADDRESS
FROM Table2
UNION
SELECT T3_ID AS ID, T3_NAME AS NAME, T3_ADD AS ADDRESS
FROM Table3

我得到了下面的結果。

我的問題是，如何添加一個名為 TYPE 的列（欄位）並將值分配給查詢結果，但不更新現有的三個表以使其像下面的螢幕截圖一樣？

不是最優雅的解決方案，但要回答您的問題，您可以這樣做：

SELECT T1_ID AS ID, T1_NAME AS NAME, T1_ADD AS ADDRESS, 'ANIMAL' AS TYPE
FROM Table1
UNION
SELECT T2_ID AS ID, T2_NAME AS NAME, T2_ADD AS ADDRESS, 'HUMAN' AS TYPE
FROM Table2
UNION
SELECT T3_ID AS ID, T3_NAME AS NAME, T3_ADD AS ADDRESS, 'OBJECT' AS TYPE
FROM Table3

引用自：https://dba.stackexchange.com/questions/251791