NULL values appear when taking the sum of two columns taken from Lookup tables

I am using SQL Server and taking data from two lookup tables and want to take the sum of these two columns.

The problem arises when the sum of these two columns (lookup values) gives NULL values. However, I have used COALESCE to change the NULL values to zero.

The line I am calculating the sum is this one: (t2.[Score]+t3.[Score]) as Total

select  t1.[ID]
      ,t1.[District]
      ,[CLLG_Interventiond]
      ,t1.[UC_HH]
      ,t1.[Benef_Household]
      ,t1.[Duration_Years]
      ,t1.[Duration_Months]
      ,t1.[Budget_PKR]
      ,t1.[Priority]
      ,COALESCE(t2.[Score],0) as E_Score
      ,COALESCE(t3.[Score],0) as UCDP_Score
      ,(t2.[Score]+t3.[Score]) as Total
  FROM [dbo].[Data] as t1
  left outer join E_Growth as t2
  on t1.CLLG_Interventiond = t2.Intervention
  left outer join UCDP as t3
 on  t1.Priority = t3.Priority

Try to use COALESCE for the values in the SUM
Like this:

COALESCE(t2.[Score],0) + COALESCE(t3.[Score],0) as Total

The query will look like this:

select  t1.[ID]
      ,t1.[District]
      ,[CLLG_Interventiond]
      ,t1.[UC_HH]
      ,t1.[Benef_Household]
      ,t1.[Duration_Years]
      ,t1.[Duration_Months]
      ,t1.[Budget_PKR]
      ,t1.[Priority]
      ,COALESCE(t2.[Score],0) as E_Score
      ,COALESCE(t3.[Score],0) as UCDP_Score
      ,COALESCE(t2.[Score],0) + COALESCE(t3.[Score],0) as Total
  FROM [dbo].[Data] as t1
  left outer join E_Growth as t2
  on t1.CLLG_Interventiond = t2.Intervention
  left outer join UCDP as t3
 on  t1.Priority = t3.Priority

StackExchange Database Administrators Q#315304, answer score: 13