sql union 显示重复

Question

image of what I want

I have tried the join on x or y and it didn't work, even the group by didn't work. What almost gave me the result is the query below

SELECT A.Id ,A.AccNo ,A.Name ,B.Id ,B.AccNo1 ,B.AccNo2 ,B.Name 
   from Table1  as A 
   left outer  join Table2 as B on A.AccNo = B.AccNo1 
union 
 SELECT A.Id ,A.AccNo ,A.Name ,B.Id, B.AccNo1, B.AccNo2, B.Name, 
   from Table1 as A 
   left outer  join Table2 as B on A.AccNo = B.AccNo2

After getting the query correct I want to show only the exceptions where there was no link between the tables and its kind of difficult if the T1.ID is repeated

Answer 1

You seem to want a left join :

select t1.*, t2.*
from table1 t1 left join
     table2 t2
     on t1.id in (t2.accno1, t2.accno2);

Answer 2

Try:

SELECT A.Id ,A.AccNo ,A.Name ,B.Id ,B.AccNo1 ,B.AccNo2 ,B.Name 
from Table1  as A 
left outer  join Table2 as B 
ON A.AccNo = (CASE WHEN  A.AccNo = B.AccNo1 THEN B.AccNo1 ELSE B.AccNo2 END)

Answer 3

You may nest your original query, and then use max aggregate function with grouping :

SELECT Id ,AccNo ,Name, max(Id2) as Id2, max(Name2) as Name2,
       max(AccNo1) as AccNo1, max(AccNo2) as AccNo2
  FROM
(
  SELECT A.Id ,A.AccNo ,A.Name ,B.Id Id2 ,B.AccNo1 ,B.AccNo2 ,B.Name Name2
     from Table1  as A 
     left outer  join Table2 as B on A.AccNo = B.AccNo1 
  union 
   SELECT A.Id ,A.AccNo ,A.Name ,B.Id Id2, B.AccNo1, B.AccNo2, B.Name Name2
     from Table1 as A 
     left outer  join Table2 as B on A.AccNo = B.AccNo2
) q  
GROUP BY Id ,AccNo ,Name;

SQL Fiddle Demo

Answer 4

Do a LEFT JOIN to return the table1 values along with matching table2 values (where t2.accno2 = t1.accno):

select t1.*, t2.*
from table1 t1
left join table2 t2
     on t1.accno = t2.accno2

Or, perhaps you want table2 values for matching accno1's as well?

select t1.*, t2.*
from table1 t1
left join table2 t2
     on t1.accno in (t2.accno1, t2.accno2)

Answer 5

It this way to resolve:

SELECT
 t1.id,
 t1.accno,
 t1.name,
 (
     SELECT DISTINCT
         id
     FROM
         table2
     WHERE
         accno2 = t1.accno
 ),
 (
     SELECT DISTINCT
         name
     FROM
         table2
     WHERE
         accno2 = t1.accno
 ),
 (
     SELECT DISTINCT
         accno1
     FROM
         table2
     WHERE
         accno2 = t1.accno
 ),
 (
     SELECT DISTINCT
         accno2
     FROM
         table2
     WHERE
         accno2 = t1.accno
 ) FROM
 table1 t1
 LEFT JOIN table2 t2 ON t1.accno = t2.accno1 OR t1.id = t2.id