query to ignore duplicate/null records

Question

Below are the 3 tables which we need to join to get the data

 TableA         TableB               TableC
    AId          BId     Name      CId       DeclareDate         


        

Answer 1

use left join into table C

  select a.*,b.*, c.DeclareDate, c.Value from TableA a
   inner join TableB b on  a.AI =b.BId
  left join 
  (select * from TableC where DeclareDate='December') c
   on b.BId = c.CId

OUTPUT