Full outer join not returning all rows?

Question

I have a table that contains multiple records for multiple dates.

I am trying to see the difference between \"date 1\" and \"date 2\" and my full outer join is not r

Answer 1

The where is killing the outer join.
A column cannot be both null and = to a value.
Put the conditions in the join.

SELECT COALESCE(c.AccountBranch, p.AccountBranch)
     , COALESCE(c.AccountNumber, p.AccountNumber)
     , COALESCE(c.AccountSuffix, p.AccountSuffix)
     , c.PrincipleAmount, p.PrincipleAmount
FROM            cb_account_extension_principle_dpd c
FULL OUTER JOIN cb_account_extension_principle_dpd p
  ON p.AccountBranch = c.AccountBranch
 AND p.AccountNumber = c.AccountNumber 
 AND p.AccountSuffix = c.AccountSuffix
 AND c.BusinessDataDate = @CurrentBusinessDataDate
 AND p.BusinessDataDate = @PreviousBusinessDataDate