Question

我停留在转换varchar列计划，其中包含以下数据0,1,2,3,4,8,9,10,11,12,15,16,17,18 ，19到INT。我知道，请不要问为什么这个计划专栏最初没有创建为INT，长篇大论。

所以我尝试了这个，但它不起作用。并给我一个错误：

select CAST(schedule AS int) from shift_test:

查询应检查是否在使用下面的SQL代码提交的计划中找到代表天数的数字

select empid, case when ((DateDiff(hour,'01-01-2014 07:00' , '01-01-2014 00:00')/ 24 )% 15) in ( CAST(schedule AS int))
then 'A' else '*' end as shift_A from Shift_test

执行后我收到此错误。

将varchar值转换为int时转换失败。

任何帮助都会受到欢迎

Answer 1

如果您使用的是版本2008或2008R2，请使用ISNUMERIC()测试。在SQL SERVER 2012中，您可以使用TRY_CAST()函数，该函数检查是否允许给定文字进行数据转换。

模拟SQL Server 2008 / R2的代码：

Select col1, col2,
case
   when <condition> and isnumeric(col2) then cast(col2 as int)
   else <do whatever...>
end
as converted_col2
from <yourtable>;

对于SQL Server 2012：

Select col1, col2,
case
   when <condition> then try_cast(col2 as int)
   else <do whatever...>
end
as converted_col2
from <yourtable>;

SQl Server 2008示例

declare @T table (empid int, schedule varchar(2)) ;

insert into @T(empid, schedule) values (1, '1');
insert into @T(empid, schedule) values (2, '2');
insert into @T(empid, schedule) values (3, '03');
insert into @T(empid, schedule) values (4, '4');
insert into @T(empid, schedule) values (5, '05');
insert into @T(empid, schedule) values (6, 'A');

select empid, 
   case
    when ISNUMERIC(schedule) = 1 
       and ((DateDiff(hour,'01-01-2014 07:00' , '10-01-2014 00:00')/ 24 )% 15)  
       in ( CAST(schedule AS int)) then 'A'
    else '*' 
   end 
   as shift_A 
from @T;

Answer 2

@Binaya我添加了我的代码以获得更多帮助。

计划列包含（0,1,2,3,4,8,9,10,11,12,15,16,17,18,19），它们是varchar。我想输出 A ，如果在此计算后((DateDiff(hour,'01-01-2014 07:00',startdate)/ 24 )% 15)，则在计划列中找到结果，如果在计算后找不到结果输出 * < / p>

;with Shift_runover  (shift_code,schedule,endd,startdate)
    -- Start at the beginning of shift.
    as 
    (select shift_code,schedule,Cast(end_date as DateTime) as endd,Cast(start_date as DateTime)as startdate from dbo.Shift_test
    union   all 

    -- Add hours up to the desired end date.
    select shift_code,schedule,endd,DateAdd(hour, 1,startdate)from Shift_runover where startdate<=endd),

    Extendedsamples as 
    (
    -- Calculate the number of days since the beginning of the first shift on 1/1/2014.
    select shift_code,schedule,startdate,DateDiff(hour,'01-01-2014 07:00',startdate)/ 24 as Days from Shift_runover ),
    Shifts as
     (
     -- the schedule column contain (0, 1, 2, 3,4,8,9,10,11,12,15,16,17,18,19) which is varchar.
     -- i want to output A if ((DateDiff(hour,'01-01-2014 07:00',startdate)/ 24   )% 15) is found in the schedule colume 
    select *,
    case when (DateDiff(hour,'01-01-2014 07:00',startdate)/ 24   )% 15 in(schedule)
    then 'A' else '*' end as shift_A

    from ExtendedSamples 
    )
    select *
    from Shifts
    option ( maxrecursion 0 )

用于将varchar列转换为int的sql代码

2 个答案: