Question

我有2个查询，我用它根据标志值

获取值的总和

SELECT SUM(stock_deliveries.stockValue) AS stockValues1
FROM `stock_deliveries`
LEFT JOIN `delivery` ON `delivery`.`pk_deliveryId`  = `stock_deliveries`.`fk_deliveryId`
WHERE `stock_deliveries`.`fk_stockID` = '189'
AND `delivery`.`delivery_completed` = '1'

SELECT SUM(stock_deliveries.stockValue) AS stockValues2
FROM `stock_deliveries`
LEFT JOIN `delivery` ON `delivery`.`pk_deliveryId`  = `stock_deliveries`.`fk_deliveryId`
WHERE `stock_deliveries`.`fk_stockID` = '189'
AND `delivery`.`delivery_completed` = '0

是否可以在单个查询中合并此2查询？提前谢谢。

Answer 1

是的，您在CASE WHEN等聚合函数中使用条件聚合（即SUM）：

select
  sum(case when d.delivery_completed = 0 then sd.stockvalue end) as stockvalues0,
  sum(case when d.delivery_completed = 1 then sd.stockvalue end) as stockvalues1
from stock_deliveries sd
left join delivery d on d.pk_deliveryid = sd.fk_deliveryid
where sd.fk_stockid = 189;

Answer 2

您可以在GROUP BY

的帮助下使用单个查询

SELECT SUM(stock_deliveries.stockValue) AS stockValues, `delivery`.`delivery_completed` as deliveryCompleted
FROM `stock_deliveries`
LEFT JOIN `delivery` ON `delivery`.`pk_deliveryId` =  `stock_deliveries`.`fk_deliveryId`
WHERE `stock_deliveries`.`fk_stockID` = '189'
GROUP BY `delivery`.`delivery_completed`;

这样做，delivery_completed的每个值都有一行与相关的总和（如果你只需要0和1值，你可以添加到where子句and delivery.delivery_completed IN (0,1)）。例如：

stockValues    deliveryCompleted
       1000           0
        700           1

Answer 3

你可以使用＆＃34;如果＆＃34;内部总和，以检查您是否需要stockValues1或stockValues0

中的值

SELECT SUM(IF(d.delivery_completed = 1, sd.stockValue, 0)) AS stockValues1, SUM(IF(d.delivery_completed = 0, sd.stockValue, 0)) AS stockValues2
FROM stock_deliveries sd
LEFT JOIN delivery d ON d.pk_deliveryId  = sd.fk_deliveryId
WHERE sd.fk_stockID = '189'
AND (d.delivery_completed = 1 OR d.delivery_completed = 0)

显然，如果＆＃34; delivery_completed＆＃34;只有1或0，您可以省略查询中的最后一个AND;）

编辑：正如Thorsten Kettner所说，你也可以使用case-when语法，只有一个＆＃34; case＆＃34;它们基本相同。在这种情况下，if语法更简洁，但如果您有更多选项更灵活，例如：

SELECT CASE sometable 
       WHEN 'top' THEN 'high' 
       WHEN 'center' THEN 'medium' 
       ELSE 'low' 
       END AS position

Answer 4

您可以使用UNION ALL运算符来保留2个结果行的逻辑，但这些行现在是相同的结果，而不是2个分开的

如何合并检查相同标志列但值不同的2个查询

4 个答案: