我在使用Linq做如下查询时，系统报错：指定的转换无效的错误

string sql=string.Format("SELECT top 1 [ID] FROM [LianSai] where TeamID in (SELECT  [TeamID] FROM [QiuDui] where PlayerID={0} and FormStatus='Approved' ) and FormStatus='Approved' and LeagueID={1}",userID,leagueID);

var query = dataContext.ExecuteQuery<int>(sql).FirstOrDefault();