Select
              a.no
             ,a.name
             ,a.day
             ,IsNull(Sum(c.jumsu),0)
         From        
             (
                  Select
                         b.no
                        ,a.name
                        ,a.day
                    From
                        (                                                   
                          Select a.no                                             
                                ,c.name                                           
                                ,a.day                                            
                           From #table1 a                                         
                                          Full Outer Join (                       
                                                              Select a.name       
                                                                From #table1 a    
                                                            Group By a.name       
                                                           ) c                    
                                                               On 1 = 1           
                        ) a
                            Left Outer Join
                                            #table1 b
                                                      On a.name = b.name                                                            
               Group By b.no
                       ,a.name
                       ,a.day
             ) a                      
                 Left Outer Join
                                 #table1 b
                                           On a.no = b.no
                                          And a.day = b.day
                 Left Outer Join
                                 #table2 c
                                           On b.no = c.no
       Where a.day = '2014-10-01'                                   
    Group By a.no
            ,a.name
            ,a.day
    Order By a.day
            ,a.no
            ,a.name                                         
 

원하는 형태가 이게 맞는지 모르겠네요 ㅡ,ㅡ;

아우터 조인에서의 조건은
Where 절에 줄 때와 On 절에 줄 때 결과가 달라집니다.
지금 On 절에 주신게 맞구요.
Select 절에서의 If 문은 쓸데 없는 조건입니다.
이미 On 절에서 걸러졌기 때문이죠.

SELECT a.no
     , a.name
     , SUM(jumsu) jumsu
  FROM table1 a
  LEFT JOIN table2 b
    ON a.no  = b.no
   AND b.day = '2014-10-01'
 GROUP BY a.no
;

데이터가 쌓일수록 느리다면?
원인은 적절한 인덱스가 없다는 거죠.
table2(no, day) 인덱스가 있어야 합니다.
인덱스가 없다면?
대량의 아우터 조인이 부담될 수 있습니다.
이 때는 인라인뷰에서 미리 집계한 후에 조인하도록하세요

SELECT a.no
     , a.name
     , b.jumsu
  FROM table1 a
  LEFT JOIN (SELECT no
                  , SUM(jumsu) jumsu
               FROM table2
              WHERE day = '2014-10-01'
              GROUP BY no
             ) b
    ON a.no = b.no
;