Key Matching Cases
Ist Account 2nd Account
mine no match in      
  2nd account      
mm at least mm
m1 1 match m1
1m   1m
  no match in  
  1st account yours
mm means many to many
m1 means many to 1
1m means 1 to many
Example: mine
Ist Account 2nd Account Joined Account
s111               s111
s112
s112              
s121 a1   s121 b1      
s122 a2   s122 b2    
s122 a3   s121 b3      
    s231      
    s232      
Example: yours
Ist Account 2nd Account Joined Account
s111               s231
s232
s112              
s121 a1   s121 b1      
s122 a2   s122 b2    
s122 a3   s121 b3      
    s231      
    s232      
Example: mm
Ist Account 2nd Account Joined Account
s111           s121 a1 b1
s122 a2 b2
s122 a3 b2
s121 a1 b3
s112        
s121 a1   s121 b1  
s122 a2   s122 b2
s122 a3   s121 b3
    s231  
    s232
Example: m1
Ist Account 2nd Account Joined Account
s111           s121 a1 b1
s122 a2 b2
s122 a3 b2
s112        
s121 a1   s121 b1  
s122 a2   s122 b2
s122 a3   s121 b3
    s231  
    s232
Example: 1m
Ist Account 2nd Account Joined Account
s111           s121 a1 b1
s121 a1 b3
s122 a2 b2
s112        
s121 a1   s121 b1  
s122 a2   s122 b2
s122 a3   s121 b3
    s231  
    s232
Example: mine|mm
Ist Account 2nd Account Joined Account
s111           s111
s112
s121 a1 b1
s121 a1 b3
s122 a2 b2
s122 a3 b2
s112        
s121 a1   s121 b1  
s122 a2   s122 b2
s122 a3   s121 b3
    s231  
    s232
All conbinations
mine
yours
mm
m1
1m
mine|yours
mine|yours|mm
mine|yours|m1
mine|yours|1m
yours|mm
yours|m1
yours|1m
mine|mm
mine|m1
mine|1m