Joining same table multiple times in SQL [duplicate]

Answer 1

You can Case expression:

SELECT tran_ref, SUM(CASE WHEN tran_id = 1 THEN AMOUNT END) AS AMOUNT_01,
SUM(CASE WHEN tran_id = 2 THEN AMOUNT END) AS AMOUNT_02,
SUM(CASE WHEN tran_id = 3 THEN AMOUNT END) AS AMOUNT_03,
COUNT(*) count_of_ref_rows
FROM TABLE1
GROUP BY tran_ref;

Also, you can use PIVOT clause for this:

select a.*, b.count_total from
(SELECT tran_ref, [1] as amount_01, [2] as amount_02, [3] as amount_03
FROM TABLE1
PIVOT(sum(amount) FOR tran_id IN ([1] , [2], [3])) pivot_table) a
 inner join (SELECT tran_ref, count(1) count_total
FROM TABLE1 group by tran_ref) b on (a.tran_ref = b.tran_ref);