SQL 比较和 Unity 表

Question

I have 2 table, i get problem when unity they all tell that

Table 1

 Customer | Buyer | Usage | Item Code | Item Name | Month1 | Month2 

   A      Jirulu  Bottom    111111     Item1        100      50          
   B      Bakeyo  Top       122222     Item2        100      50        
   D      Sagero  Bottom    133333     Item3        100      50        

Table 2

Customer | Buyer | Usage | Item Code | Item Name | Month3 | Month4 | 

   A      Jirulu  Bottom    111111     Item1        100      50      
   C      Bakeyo  Top       122222     Item2        100      50      
   D      Sagero  Bottom    133333     Item3        100      50           

How can I get result like this:

Customer | Buyer | Usage | Item Code | Item Name | Month1 | Month2| Month3 | Month4 | 

   A      Jirulu  Bottom    111111     Item1        100      50      100      50    
   B      Bakeyo  Top       122222     Item2        100      50      100      50        
   C      Bakeyo  Top       122222     Item2         0        0      100      50
   D      Sagero  Bottom    133333     Item3        100      50      100      50   

Please advice, thankyou!

Answer 1

Below Query will help you.

SELECT tab.customer, 
       tab.buyer, 
       tab.usage, 
       tab.usage, 
       tab.itemcode, 
       tab.itemname, 
       Sum(month1) AS Month1, 
       Sum(month2) AS Month2, 
       Sum(month3) AS Month3, 
       Sum(month4) AS Month4 
FROM   (SELECT customer, 
           buyer, 
           usage, 
           itemcode, 
           itemname, 
           month1, 
           month2, 
           0 AS month3, 
           0 AS month4 
    FROM   table1 
    UNION ALL 
    SELECT customer, 
           buyer, 
           usage, 
           itemcode, 
           itemname, 
           0 AS month1, 
           0 AS month2, 
           month3, 
           month4 
    FROM   table2) tab 
GROUP  BY tab.customer, 
      tab.buyer, 
      tab.usage, 
      tab.usage, 
      tab.itemcode, 
      tab.itemname 

Answer 2

Other than the UNION already shown it's possible to JOIN the two table, in this case having different customer in the two table a FULL JOIN

SELECT Coalesce(t1.[Customer], t2.[Customer]) [Customer]
     , Coalesce(t1.[Buyer], t2.[Buyer]) [Buyer]
     , Coalesce(t1.[Usage], t2.[Usage]) [Usage]
     , Coalesce(t1.[Item Code], t2.[Item Code]) [Item Code]
     , Coalesce(t1.[Item Name], t2.[Item Name]) [Item Name]
     , Coalesce([Month1], 0) [Month1]
     , Coalesce([Month2], 0) [Month2]
     , Coalesce([Month3], 0) [Month3]
     , Coalesce([Month4], 0) [Month4]
FROM   Table1 t1
       FULL JOIN Table2 t2 ON t1.Customer = t2.Customer 
                          and t1.Buyer = t2.Buyer 
                          and t1.[usage] = t2.[usage]
                          and t1.[Item Code] = t2.[Item Code]
                          and t1.[Item Name] = t2.[Item Name]
ORDER BY Coalesce(t1.[Customer], t2.[Customer])

On a side note if you have vertical partition it'l be a lot better if you create a key to join the partition that is shorter, for example you can divide the key section and add a fake ID to relate to the other partition, something like

ID | Customer | Buyer | Usage | Item Code | Item Name

ID | Month1 | Month2

ID | Month3 | Month4