Question

我有以下查询：

select *, 
case when prod='CPU' and quan>1000 then 1000
     when prod='MOUSE' and quan>1024 then 1024
     when prod='MONITOR' and quan<2 then 2 else quan end as quan
from products_test;

我收到错误：将varchar值'CPU'转换为数据类型int时转换失败。

Answer 1

更新：根据问题作者的以下评论

我改变了你所描述的代码，但它还在抛出一个错误。＆＃34;转换varchar值时转换失败＆＃39; 23787.1＆＃39;到数据类型int＆＃34;

在quan类型而不是varchar中看起来像numeric，而且在错误更改时，已确认prod被定义为integer }。

select *, 
case when CAST(prod AS VARCHAR(MAX))='CPU' and CAST(quan as DECIMAL(10,4))>1000 then 1000
     when CAST(prod AS VARCHAR(MAX))='MOUSE' and CAST(quan as DECIMAL(10,4))>1024 then 1024
     when CAST(prod AS VARCHAR(MAX))='MONITOR' and CAST(quan as DECIMAL(10,4))<2 then 2 else  CAST(quan as DECIMAL(10,4)) end as quan
from products_test;

旧回答：请尝试修改后的查询：
select *, 
case when CAST(prod AS VARCHAR(MAX))='CPU' and quan>1000 then 1000
     when CAST(prod AS VARCHAR(MAX))='MOUSE' and quan>1024 then 1024
     when CAST(prod AS VARCHAR(MAX))='MONITOR' and quan<2 then 2 else quan end as quan
from products_test;
如果此方法成功，Prod实际上定义为int和您永远无法在then语句中获得CASE（真实案例）值。

您可能需要比较主表中的代码或外键，其值为'CPU', 'MOUSE' and 'MONITOR'和prod。

使用case语句时的转换错误 - Sql Server

1 个答案: