mysql - 选择案例不起作用＃1064

我对此有疑问

SELECT
CASE WHEN QuantityPart =< Threshold
               THEN (Threshold - QuantityPart) + Threshold
       END as RecommendedReorderQuantity, *
FROM parts, stock

有人可以帮忙吗？

SELECT *,
       CASE WHEN QuantityPart =< Threshold
            THEN (Threshold - QuantityPart) + Threshold
       END as RecommendedReorderQuantity
FROM parts INNER JOIN stock
        ON parts.PartID = stock.PartID

最佳答案

*应该先出现在您的CASE饱足感之前，另一件事是

<=不是=<

SELECT *,
       CASE WHEN QuantityPart <= Threshold
            THEN (Threshold - QuantityPart) + Threshold
       END as RecommendedReorderQuantity
FROM parts, stock

作为附带说明，该查询产生笛卡尔积。如果这不是您想要的，则需要提供链接条件，例如

SELECT *,
       CASE WHEN QuantityPart <=  Threshold
            THEN (Threshold - QuantityPart) + Threshold
       END as RecommendedReorderQuantity
FROM parts INNER JOIN stock
        ON parts.columnName = stock.columnName

其中columnName是定义它们之间关系的列。

关于mysql - 选择案例不起作用＃1064，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/14764077/

threshold

mysql - 选择案例不起作用＃1064