Root1      TBLA      KEY1      COLA      A    B    
Root1      TBLA      KEY1      COLB      D    E    
Root1      TBLA      KEY3      COLX      M    N     
Root2      TBLB      KEY4      COLX      M    N     
Root2      TBLB      KEY4      COLD      A    B   
Root3      TBLC      KEY5      COLD      A    B