SQL Server-条件使用的位置

我想在下面的select sql代码中添加条件

select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
      (CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)'
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
      (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
from #output
where line like '[A-Z][:]%'
order by drivename

结果是

drivename   capacity(GB)    freespace(GB) 
C:\            120                36 
D:\            100                 7

我想添加这样的内容：“自由空间（GB）>10”

如何添加此条件？

使用CTE或子查询：

;WITH cte as
(
select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
      (CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)'
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
      (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
from #output
where line like '[A-Z][:]%'
)
SELECT *
FROM cte
WHERE [freespace(GB)] > 10
order by drivename;

其次，这是不理解的典型例子

---

如果您只想显示C:\信息，则上述查询可以执行。

有多种方法可以执行此操作

Temp table

和

CTE

看起来可能是一样的，但试着从不同的角度理解它们之间的区别

使用临时表

通过使用CTE

直接使用where子句中的条件

---

@Sezer可以尝试使用

和round（cast（rtrim（ltrim（子字符串（行，CHARINDEX（'%'，行）+1，（CHARINDEX（'*'，行）-1）-CHARINDEX（'%'，行）））作为Float）/1024，0）>10

，但您的代码将被复制并uglier@Abhishek仅使用表达式的一部分，计算freesize有两行

select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
      (CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)'
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
      (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
from #output
where line like '[A-Z][:]%'
AND round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
      (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0) > 10
order by drivename

select * into ##t from 
    (select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename,
    round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
    (CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)',
    round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
    (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
    from #output
    where line like '[A-Z][:]%') as T

Select * from ##t where [freespace(GB)] > 10 order by drivename

;WITH cte as
(
select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
      (CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)'
      ,round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
      (CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
from #output
where line like '[A-Z][:]%'
)

SELECT * FROM cte WHERE [freespace(GB)] > 10 order by drivename;

select rtrim(ltrim(SUBSTRING(line,1,CHARINDEX('|',line) -1))) as drivename,
round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('|',line)+1,
(CHARINDEX('%',line) -1)-CHARINDEX('|',line)) )) as Float)/1024,0) as 'capacity(GB)',
round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
(CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)as 'freespace(GB)'
from #output
where line like '[A-Z][:]%'
And (round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
(CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)) > 10
order by drivename