Question

我有一个表EmployeeAttendance和Users，当我尝试使用以下查询获取记录并将空值传递给@userName参数时，它不会返回任何记录...查询中可能存在一些问题。 ..

任何人都可以帮助我吗

 declare @month int =12, 
@year int=1,
@orgID int=1,
@userName nvarchar(100) = null;

DECLARE  @lastDay int;

-- calculations
DECLARE @startDate datetime, @endDate datetime
SET @startDate =  convert(varchar, @year) + '-' + convert(varchar, @month) + '-1'
set @endDate = DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,@startDate)+1,0))
set @lastDay =  day(@endDate) --last day of month

declare @day int
set @day = 2


declare @days varchar(max)
set @days = '[1]'
WHILE (@day <= @lastDay)
BEGIN
   set @days = @days + ',[' + convert(varchar, @day) + ']'
   set @day = @day + 1
END

declare @query varchar(max)

set @query = '
SELECT USerID,Name,' + @days  +
'
FROM
(

SELECT u.ID as UserID, u.FirstName + '' ''' + ' ' + ' + u.LastName as Name, InTime,Outtime,isPresent, day(Date) as day FROM users u
LEFT join EmployeeAttendance e on e.USerID = u.ID AND [Date] between '''+ cast( @startDate as varchar)+' '' and '''+ cast( @endDate as varchar)+' '' 
left join Employee emp on emp.UserID= u.ID

where emp.OrganisationID =' +cast( @orgID as varchar)+'

and(u.UserName like ''%'+@userName+  '%'' OR '''+@userName+''' IS NULL)

) AS SourceTable
PIVOT
(
MAX(InTime)
FOR day IN ( ' + @days + ')' + '
) AS PivotTable


;'

print @query;

exec(@query);





GO

当我使用某个特定字符串传递@userName时，它会返回正确的结果，但如果我将空值传递给@userName，则它将返回任何内容。

所以我想，当我将null值传递给@userName时，它会返回所有结果。

Answer 1

哦，是的。这儿存在一个问题。如果您对字符串返回null，则整个字符串将为null。 'abc'+ null = null

不要将其声明为null

@userName nvarchar(100) = '';

并改变

(u.UserName like ''%'+@userName+  '%'' OR '''+@userName+''' ='''' )

存储过程不返回所需结果

1 个答案: