select distinct
       CLFIIK.AdID
      ,CLFIIK.AdGiverName
      ,CLFIIK.AdGiverEmail
      ,CLFIIK.Title
      ,left(CLFIIK.Descripton,200) +'...' as Descripton -- select 200 Caharacter and after 200 char it will add ...
      , case
           when CLFIIK.type = 1 then -- Wanted Events
            'Wanted Event'
          when  CLFIIK.type = 1 then -- offering Events
            'Offering Event'
          else -- Neither Wanted no Offering Events
               'No Event Yet'
        end as Type
         ,CASE
           WHEN DATEDIFF(HOUR, PublishedDate, GETDATE()) < 24 THEN
               CASE DATEDIFF(HOUR, PublishedDate, GETDATE())
                   WHEN 1 THEN
                      CONVERT(VARCHAR, DATEDIFF(HOUR, PublishedDate, GETDATE())) + ' hour ago'
                   ELSE
                      CONVERT(VARCHAR, DATEDIFF(HOUR, PublishedDate, GETDATE())) + ' hours ago'
               END
          ELSE
         REPLACE(CONVERT(VARCHAR, PublishedDate, 6), ' ', '-')
       END as PublishedDate
       ,CLFIIK.LastModifiedDate
       ,LM.LocalityName +', '+ CityM.CityName as Address
       ,CM.CategoryName
       ,CM.CategoryID
 from CLF.utblCLFAdInstanceInfoKeys as CLFIIK
 inner join
      dbo.utblCategoryMaster as  CM on CM.CategoryID = CLFIIK.CategoryID
 inner join
      dbo.utblLocalityMaster as LM on LM.LocalityID = CLFIIK.LocalityID
 inner join
      dbo.utblCityMaster as CityM on CityM.CityID = LM.CityID
 left join
      CLF.utblCLFAdInstanceDtls as AdInsDeets on AdInsDeets.AdID = CLFIIK.AdID
where  @WhereClause;

Msg 4145, Level 15, State 1, Procedure udspGetCLFSearchResultEventList, Line 55
   An expression of non-boolean type specified in a context where a condition is expected, near ';'.

DECLARE @sql nvarchar(2000) = 'SELECT ....  FROM ....'
DECLARE @sqlwithwhere nvarchar(2000)
SET @sqlwithwhere = @sql + @WhereClause
EXEC sp_executesql @sqlwithwhere