减少SQL代码

Question

以下SQL代码位于where子句中。有没有其他的方法可以写出来缩短这一点。下面的代码重复了很多次。我想缩短此代码

((Business_Unit = 'A' 
and ((
convert(money, case when substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) = '-' 
then substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) else 
substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) end) 
) >= 100)) 
OR 


(Business_Unit = 'B' 
AND ((
convert(money, case when substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) = '-' 
then substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) else 
substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) end) 
) >=100.00) 
AND (text7 != 'N') 
OR 

Business_Unit = 'B' 
AND ((
convert(money, case when substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) = '-' 
then substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) else 
substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) end) 
) >=100.00) 
AND (text7 = 'N') 
and (text4 != '') 
OR Business_Unit = 'B' 
AND ((
convert(money, case when substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) = '-' 
then substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) else 
substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) end) 
) > 300.00) 
AND (text7 = 'N') 
and (text4 = '')) 
OR 
(Business_Unit = 'C' 
and ((
convert(money, case when substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) = '-' 
then substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) else 
substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) end) 
) >= 150)`enter code here` 
and text1 != 'N') 

Answer 1

我会在这里使用CTE。我们的想法是为您的where子句准备数据：

;with cte as 
(--your current query here without where clasuse 
--just add the following to the select list 
convert(money, case when substring(ltrim(rtrim(premium_change)), 
            len(ltrim(rtrim(premium_change))), 
            1) = '-' 
        then substring(ltrim(rtrim(premium_change)), 1, 
            len(ltrim(rtrim(premium_change))) 
            - 1) 
        else substring(ltrim(rtrim(premium_change)), 1, 
            len(ltrim(rtrim(premium_change)))) 
       end) as pc 
) 
select * from cte 
where 
    (Business_Unit = 'A' and pc >= 100) or 
    (Business_Unit = 'B' and pc >= 100 and text7 != 'N') or 
    ... 

我无法解析您的怪异AND OR组合（这似乎不正确反正）。

如果使用CTE是不可能的，你可以缩短如下：

substring(ltrim(rtrim(premium_change)),len(ltrim(rtrim(premium_change))),1) 

变为：

right(ltrim(rtrim(premium_change)), 1) 

和：

substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change))) -1) 

变为：

left(ltrim(rtrim(premium_change)), len(ltrim(rtrim(premium_change))) -1) 

和：

substring(ltrim(rtrim(premium_change)),1,len(ltrim(rtrim(premium_change)))) 

变为：

ltrim(rtrim(premium_change))