Question

我想在下面选择sql代码添加条件。

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

我想添加如下：'freespace（GB）＆gt; 10'

我如何添加此条件？

Answer 1

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 Logical Query Processing

的典型示例

Answer 2

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

如果您只想显示上述查询可以执行的C：\信息。

Answer 3

执行此操作的多种方式.. Temp table和CTE似乎相同，但尝试从here.

了解它们之间的区别

使用临时表

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

使用CTE

;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;

直接使用where子句中的条件

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][:]%'
And (round(cast(rtrim(ltrim(SUBSTRING(line,CHARINDEX('%',line)+1,
(CHARINDEX('*',line) -1)-CHARINDEX('%',line)) )) as Float) /1024 ,0)) > 10
order by drivename

SQL Server - 条件用法

3 个答案: