[Solved] join two columns with same title but in different table


You can use LEFT JOIN and then get SUM of the AMOUNT by grouping rows with the same CUST_ID :

SELECT t2.CUST_ID
     , COALESCE(SUM(t1.AMOUNT), 0) AS TOTAL
FROM cus t2 LEFT JOIN pur t1 ON t1.CUST_ID = t2.CUST_ID
GROUP BY  t2.CUST_ID
ORDER BY TOTAL

SQLFiddle

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solved join two columns with same title but in different table