Error SQL query: Use SUM method, When #1054 - Unkn

问题:

When us table customer id than getting error #1054 - Unknown column 'tbl_customers.id' in 'where clause' Actually problems is Every derived table must have its own alias.

Like this query following.

SELECT tbl_customers.*,(SELECT SUM(amount) As Amount
FROM 
(
    SELECT tcc.entry_fees*COUNT(tccc.match_contest_id) as amount 
    FROM `tbl_cricket_customer_contests` tccc 
    LEFT JOIN tbl_cricket_contest_matches tccm on(tccm.id=tccc.match_contest_id) 
    LEFT JOIN tbl_cricket_contests tcc ON (tcc.id=tccm.contest_id) 
    WHERE tccc.customer_id = tbl_customers.id GROUP BY tccc.match_contest_id
) As DT) as spendamount
FROM (`tbl_customers`) 
WHERE `tbl_customers`.`is_deleted` = 'N' 
GROUP BY `tbl_customers`.`id` 
ORDER BY `spendamount` DESC

Below table relationship structure following this in query.

回答1:

You where using tbl_customers on the subquery where you didnt had access to it. You just had to join instead of using where:

SELECT tbl_customers.*,(SELECT SUM(amount) As Amount
FROM 
(
    SELECT tcc.entry_fees*COUNT(tccc.match_contest_id) as amount 
    FROM `tbl_cricket_customer_contests` tccc 
    JOIN `tbl_customers` ON (tccc.customer_id = tbl_customers.id)
    LEFT JOIN tbl_cricket_contest_matches tccm on(tccm.id=tccc.match_contest_id) 
    LEFT JOIN tbl_cricket_contests tcc ON (tcc.id=tccm.contest_id) 
    GROUP BY tccc.match_contest_id
) As DT) as spendamount
FROM (`tbl_customers`) 
WHERE `tbl_customers`.`is_deleted` = 'N' 
GROUP BY `tbl_customers`.`id` 
ORDER BY `spendamount` DESC

回答2:

I'm not sure this will work for MySql, but try to move the derived table from the subquery to the from clause (Note: I've changed the group by column of the derived table, but I think it should be O.K in this case):

SELECT tbl_customers.*,(SELECT SUM(amount) As FROM DT) as spendamount
FROM `tbl_customers`
INNER JOIN
(
    SELECT tccc.customer_id, tcc.entry_fees * COUNT(tccc.match_contest_id) as amount 
    FROM `tbl_cricket_customer_contests` tccc 
    LEFT JOIN tbl_cricket_contest_matches tccm on(tccm.id=tccc.match_contest_id) 
    LEFT JOIN tbl_cricket_contests tcc ON (tcc.id=tccm.contest_id) 
    GROUP BY tccc.customer_id 
) As DT
    ON dt.customer_id = `tbl_customers`.`id` 
WHERE `tbl_customers`.`is_deleted` = 'N' 
GROUP BY `tbl_customers`.`id` 
ORDER BY `spendamount` DESC

回答3:

If I want the total amount, don't nest the aggregation functions and remove the group by:

SELECT tbl_customers.*,(SELECT SUM(tcc.entry_fees) as amount 
                        FROM tbl_cricket_customer_contests tccc 
                        JOIN tbl_cricket_contest_matches tccm ON tccm.id = tccc.match_contest_id 
                        JOIN tbl_cricket_contests tcc ON tcc.id = tccm.contest_id 
                        WHERE tccc.customer_id = tbl_customers.id ) as spendamount
FROM (`tbl_customers`) 
WHERE `tbl_customers`.`is_deleted` = 'N' 
GROUP BY `tbl_customers`.`id` 
ORDER BY `spendamount` DESC

I also changed the LEFT JOIN to JOIN. You are summing values from the last table, so only matching rows contribute to the sum.