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sqlgroup-bysubqueryleft-joinon-clause

How can I remove subquery?

I need to remove the subquery. But I must maintain the condition. What can I do?

(SELECT * FROM customer_orders where status=3)


SELECT cus.id,cus.customer_name,cus.mobile,cus.email, 
COUNT(CAST(cus_ord.customer_id AS INT)) AS Total_Order ,SUM(cus_ord.order_total_amt) AS Total_Amount
FROM customers as cus
LEFT JOIN (SELECT * FROM customer_orders where status=3) as cus_ord on CAST(cus_ord.customer_id AS INT)= CAST(cus.id AS INT)
GROUP BY CAST(cus.id AS INT)
Solution

  • You can move the condition in the ON clause:

    ......................
FROM customers AS cus LEFT JOIN customer_orders AS cus_ord 
ON CAST(cus_ord.customer_id AS INT) = CAST(cus.id AS INT) AND cus_ord.status = 3
......................

    Also:

    COUNT(CAST(cus_ord.customer_id AS INT))

    is equivalent to just:

    COUNT(cus_ord.customer_id)