I need to retrieve individual column from 3 different tables - mysql

Question

My Sql Server database has three tables (Amount, wthdrwl, spent), each table has got id, and amount column.
I want to retrieve the amount column from these three different tables.

Answer 1

For both MySQL, SQL-Server, use UNION (implicit distinct) or UNION ALL:
SELECT Amount FROM Amount
UNION ALL
SELECT Amount FROM wthdrwl
UNION ALL
SELECT Amount FROM spent

Answer 2

I suppose there is some relation between three tables
SELECT A.Amount AS Amount ,
W.Amount AS Withdrawal ,
S.Amount AS Spent
FROM Amount A
LEFT OUTER JOIN wthdrwl W ON A.ID = W.ID
LEFT JOIN spent S ON A.ID = S.ID
Check here- SqlFiddle

Answer 3

Given your comment above, use a fixed string to indicate which table the values came from:
SELECT 'Amount' AS source, Amount FROM Amount
UNION ALL
SELECT 'whtdrwl' AS source, Amount FROM whtdrwl
UNION ALL
SELECT 'spent' AS source, Amount FROM spent
then you can easily identify the rows. You could write a query that does this as a single row with 3 columns, but it's far easier doing it this way.

Answer 4

If you want to put them all on one line then you have to have a way to link the columns together via a 2nd column, for example a txnId column that occurs in each of the 3 tables. Then you could do something like:
SELECT Amount.Amount Amt, whtdrwl.Amount Wdrl, spent.Amount Spd
FROM Amount, whthdrwl, spent
WHERE Amount.txnId=wthdrwl.txnId
Amount.txnId=spent.txnId

Answer 5

Use the following query-
select amount.amount, wthdrwl.amount, spent.amount from amount, wthdrwl, spent where amount.amount=wthdrwl.amount and wthdrwl.amount=spent.amount;
Here you have to use the table name along with the attribute to distinctly identify the amount attribute from 3 different table. You need to check for the equality of the id attribute in all 3 tables to correspond to a particular entity in a row of the resultset.