Question

我正在使用SQL查询

select 
    datediff(hour,Convert(DateTime,Convert(DateTime, Convert(nVarChar, cast(complaintdate as datetime), 101)) + '' +  
    Convert(varchar,complainttime,114)),dateadd(mi,330,GETUTCDATE())) 
from complaintregister

它会创建一个类似

的列

No column name
  15455
  15259
  15190
  15190
  15165
   300
   200
  1000
   500

我想要一个包含值的列＆gt; 1000

Answer 1

在条件中重复表达式：

select datediff(hour,Convert(DateTime,Convert(DateTime, Convert(nVarChar, cast(complaintdate as datetime), 101)) +''+  Convert(varchar,complainttime,114)),dateadd(mi,330,GETUTCDATE()))
from complaintregister
where datediff(hour,Convert(DateTime,Convert(DateTime, Convert(nVarChar, cast(complaintdate as datetime), 101)) +''+  Convert(varchar,complainttime,114)),dateadd(mi,330,GETUTCDATE())) > 1000

查询规划器应该识别表达式是相同的，实际上只为每条记录计算一次。

或者，您可以使用嵌套查询：

select time
from (
  select datediff(hour,Convert(DateTime,Convert(DateTime, Convert(nVarChar, cast(complaintdate as datetime), 101)) +''+  Convert(varchar,complainttime,114)),dateadd(mi,330,GETUTCDATE())) as time
  from complaintregister
) x
where time > 1000

Answer 2

如果它是SQL服务器，你可以点这样的东西

    select tablename.colname from 
(select datediff(hour,Convert(DateTime,Convert(DateTime, Convert(nVarChar, cast(complaintdate as datetime), 101)) +''+  Convert(varchar,complainttime,114)),dateadd(mi,330,GETUTCDATE())) as colname
from complaintregister) as tablename
where tablename.colname > 1000

没有测试db atm，所以你必须稍微玩一下

SELECT列包含值> 1000

2 个答案: