Question

我有一个查询

SELECT MONTHNAME(o.sale_on),
       SUM(od.current_status_id=1) AS Sales,
       SUM(od.current_status_id=2) AS Refunds,
       SUM(od.current_status_id=3) AS `Partially Refunded`,
       SUM(od.current_status_id=4) AS `Pending`,
       SUM(od.price-IFNULL(od.discount,0)+IFNULL(od.additional_charges,0)) AS net_revenue,
       SUM(CASE WHEN od.current_status_id=1 THEN od.price-IFNULL(od.discount,0)+IFNULL(od.additional_charges,0) END) AS gross_revenue
FROM orders o 
   RIGHT JOIN order_detail od USING (order_id)
where 1=1
  and year(o.sale_on) = 2015
GROUP BY DATE_FORMAT(o.sale_on,'%Y-%m')
ORDER BY o.sale_on

返回这样的数据

MONTHNAME(o.sale_on) |  Sales | Refunds | PartiallyRefunded | Pending | net_revenue  | gross_revenue

January              |   67   | 0       |0                  |   0     | 5971.1600    | 5971.1600

February             |  1644  | 1       |0                  |   0     | 152.7200     |152.7200

March                |   39   |     0   |0                  |0        |0.0000        |  0.0000

我想在几个月内展示它，我该怎么做？

我尝试了另一个与master_months表进行连接的查询

SELECT MONTHNAME(o.sale_on),
       mo.month_name,
       SUM(od.current_status_id=1) AS Sales,
       SUM(od.current_status_id=2) AS Refunds,
       SUM(od.current_status_id=3) AS `Partially Refunded`,
       SUM(od.current_status_id=4) AS `Pending`,
       SUM(od.priceIFNULL(od.discount,0)+IFNULL(od.additional_charges,0)) AS net_revenue,
        SUM(CASE WHEN od.current_status_id=1 THEN od.price-IFNULL(od.discount,0)+IFNULL(od.additional_charges,0) END) AS gross_revenue
FROM master_months mo 
  LEFT JOIN orders o ON mo.month_name = MONTHNAME(o.sale_on)
  RIGHT JOIN order_detail od USING (order_id) 
WHERE 1=1
  AND YEAR(o.sale_on) = 2015
GROUP BY DATE_FORMAT(o.sale_on,'%Y-%m')
ORDER BY o.sale_on

但这不起作用。

Answer 1

在查询中混合left join和right join只是令人困惑。您需要一个left join链，从包含所有月份的表开始。其余所有联接应为left join。

然后，您的where子句正在撤消left join。您需要将年份的条件移至on子句：

SELECT . . .
FROM master_months mo LEFT JOIN
     orders o
     ON mo.month_name = MONTHNAME(o.sale_on) AND
        YEAR(o.sale_on) = 2015 LEFT JOIN
     order_detail od
     ON o.order_id = od.order_id
GROUP BY mo.month_name
ORDER BY mo.month_name

加入mysql中的所有月份都无法正常工作

1 个答案: