How to insert random numbers into sql server table ?

INSERT INTO CurrentSessionVariableDetails
    (SessionId, FirstName, LastName, AddedForId, AddedById, CompanyId, ConnectionString, DataForYear, RoleName, ManagerName, CompanyLogoPath, IncludeProfileRatings, IncludeCompetency, ManagerId, LabelForCompetency, IsPerformanceRatingWithValue, IncludeDualObjRatingRev, IncludeSignOff, IsCompetencyRatingWithValue, IncludeObjectiveRating, RecordCPD, IncludeCPDSignOff)
    Select
    (SELECT CAST(RAND() * 1000000 AS INT)) AS [RandomNumber],
    e.FirstName
    ,      e.LastName
    ,      e.Id
    ,      null as AddedById
    ,      e.Company_Id
    ,      'tesstring' as ConnectionString
    ,      m.DataForyear
    ,      (Select Name
    from Role as r with (nolock)
    where r.Id=e.Role_Id
    ) as RoleName
    ,      (Select emp.FirstName + ' ' + emp.LastName
    from Employee as emp with (nolock)
    where emp.Id=e.ManagerId) as ManagerName
    ,      c.Logo_Path
    ,      c.IncludeProfileRatings
    ,      c.IncludeCompetency
    ,      e.ManagerId
    ,      c.labelforcompetency
    ,      c.IsPerformanceRatingWithValue
    ,      c.IncludeDualObjectiveRatingReview
    ,      c.includeSignOff
    ,      c.IsCompetencyRatingWithValue
    ,      c.IncludeObjectiveRating
    ,      e.RecordCPD
    ,      c.IncludeCPDSignedOff
    from       Employee         as e with (nolock)
    inner join MidYearAppraisal as m with (nolock) on e.Id = m.MidYear_AddedFor_Id
    inner join Company          as c with (nolock) on c.Id=e.Company_Id
    Where m.isPublished =1