Adding extra column to view, which is not present in table

Question

I want to create view with union of three tables. But in result query I want one extra column like 'tableId'.

My code is like

CREATE OR REPLACE VIEW DETAILS
AS SELECT 
* FROM
(
SELECT 
    T1.ID,
    T1.AMOUNT,
    T1.STATUS,
    T1.ADDEDBY,
    T1.ADDEDON
FROM Table1 T1
UNION ALL
SELECT 
    T2.ID,
    T2.AMOUNT,
    T2.STATUS,
    T2.ADDEDBY,
    T2.ADDEDON
FROM Table2 T2
UNION ALL
SELECT
    T3.ID,
    T3.BILLAMOUNT,
    T3.STATUS,
    T3.ADDEDBY,
    T3.ADDEDON  
FROM Table3 T3
);

This gives me union of required three tables. But how can i get table Id column in resulted output? This column is not present in any of the three tables.

Answer 1

It sounds like you just want to add an additional hard-coded value to your SELECT list

CREATE OR REPLACE VIEW DETAILS
AS SELECT 
* FROM
(
SELECT 
    T1.ID,
    T1.AMOUNT,
    T1.STATUS,
    T1.ADDEDBY,
    T1.ADDEDON,
    'T1' tableID
FROM Table1 T1
UNION ALL
SELECT 
    T2.ID,
    T2.AMOUNT,
    T2.STATUS,
    T2.ADDEDBY,
    T2.ADDEDON,
    'T2' tableID
FROM Table2 T2
UNION ALL
SELECT
    T3.ID,
    T3.BILLAMOUNT,
    T3.STATUS,
    T3.ADDEDBY,
    T3.ADDEDON,
    'T3' tableID  
FROM Table3 T3
);