Mysql左加入和总和不能按月和年正确地与组

Question

I want to get a sum of total_amount and received_amt with group by with month and year on mysql . But I am facing a problem. The problem is second table column sum not correct with group by month and year.

Current Query

SELECT t1.order_date,sum(IFNULL(t1.received_amt, 0)) as SumOfNO,
sum(IFNULL(t2.total_amount, 0)) as SumOfSM,
SUM(IFNULL(t1.received_amt, 0)  + IFNULL(t2.total_amount, 0)) AS Total
FROM `new_order` t1
LEFT JOIN
 (  select t2.sell_date,t2.total_amount, sum(total_amount) as Amount
    from sell_master t2
    group by YEAR(t2.sell_date), MONTH(t2.sell_date) 
 ) t2
 ON format(t1.order_date,'yyyy-MM') = format(t2.sell_date,'yyyy-MM')
GROUP BY YEAR(t1.order_date), MONTH(t1.order_date)
ORDER BY t1.order_date DESC

Example:

First Table: new_order

Second Table: sell_master

Table Structure:

new_order

+----------------------------------------+
|order_date(date) | received_amt(double) |
+----------------------------------------+
|2007-10-06       | 245                  |
|2007-10-06       | 310                  |                             
|2007-10-06       | 275                  |                             
|2007-10-06       | 300                  |
+----------------------------------------+

sell_master

+----------------------------------------+
|sell_date(date)  | total_amount(double) |
+----------------------------------------+
|2007-10-06       | 10                   |
+----------------------------------------+

Current Result

+---------------------------------------+
|order_date | SumOfNO | SumOfSM | Total |
+---------------------------------------+
|2007-10-06 | 1130    | 40      |1170   |
+---------------------------------------+

Expected Result

+---------------------------------------+
|order_date | SumOfNO | SumOfSM | Total |
+---------------------------------------+
|2007-10-06 | 1130    | 10      |1140   |
+---------------------------------------+

Answer 1

You shouldn't use SUM(t2.total_amount) in the main query. You already calculated the sum in the subquery, you should use that. What's happening is that you're multiplying t2.total_amount by the number of rows in new_order that matches.

There's also no need to use IFNULL() inside SUM() , since SUM() ignores null values (most aggregation functions do).

The subquery should select the year and month of the date, so you can join on those directory, rather than using date_format .

And since you're grouping by month, you shouldn't select t1.order_date -- that will just pick a random day of the month from the group. You should just show the month in YYYY-MM format.

SELECT 
    DATE_FORMAT(t1.order_date, '%Y-%m') AS month,
    sum(t1.received_amt) as SumOfNO,
    IFNULL(t2.Amount, 0) as SumOfSM,
    sum(t1.received_amt) + IFNULL(t2.Amount, 0) AS Total
FROM `new_order` t1
LEFT JOIN
 (  select YEAR(t2.sell_date) AS year, MONTH(t2.sell_date) AS month,  sum(total_amount) as Amount
    from sell_master t2
    group by year, month
 ) t2
 ON YEAR(t1.order_date) = t2.year AND MONTH(t1.order_date) = month
GROUP BY month
ORDER BY month DESC

DEMO

Answer 2

You want to select an aggregate results (sums here) of one table combined with a aggregate results of another. So build both aggregates, then join.

select 
  year_month, 
  o.total as sumofno,
  coalesce(s.total, 0) as sumofsm,
  o.total + coalesce(s.total, 0) as total
from
(
  select format(order_date, 'yyyy-MM') as year_month, sum(received_amt) as total
  from new_order
  group by format(order_date, 'yyyy-MM')
) o
left join
(
  select format(sell_date, 'yyyy-MM') as year_month, sum(total_amount) as total
  from sell_master
  group by format(sell_date, 'yyyy-MM')
) s using (year_month)
order by month desc;