Question

这是我的查询

SET @date = '2019-02-12';

SELECT lds.product_id, sum(lds.amount) amount, lpp.price
FROM `log_daily_stock` lds
 JOIN (SELECT * FROM log_product_prices
       WHERE created_at <= @date
         AND product_id = lds.product_id          -- the problem is here
       ORDER BY created_at DESC) lpp
 ON lpp.product_id = lds.product_id
WHERE branch_id in (1,2)
  AND stock_date = @date
GROUP BY product_id, price

正如我在查询中评论的那样，lds.product_id不被称为列并抛出：

＃1054-“ where子句”中的未知列“ lds.product_id”

任何想法我该如何解决？

我想要做的就是获得该产品的最新价格。这就是为什么我将created_at依次订购为DESC和LIMIT 1的原因。

Answer 1

您可以尝试以下操作

SELECT lds.product_id, sum(lds.amount) amount, lpp.price
FROM `log_daily_stock` lds
 JOIN (SELECT * FROM log_product_prices
       WHERE created_at <= @date            
       ) lpp
 ON lpp.product_id = lds.product_id
WHERE branch_id in (1,2)
  AND stock_date = @date
GROUP BY lds.product_id, lpp.price

Answer 2

一种方法是相关子查询：

SELECT lds.product_id, sum(lds.amount) as amount, 
       (SELECT lpp.price
        FROM log_product_prices lpp
        WHERE lpp.created_at <= @date AND
              lpp.product_id = lds.product_id  
        ORDER BY created_at DESC
       ) as price_asof_date       
FROM `log_daily_stock` lds
WHERE branch_id in (1, 2) AND stock_date = @date
GROUP BY product_id, price

如何在子查询中使用外部表的名称？

2 个答案: