How do I select unique values in a single column with multiple column selected?

Question

the query is actually fine and running but it doesn't select distinct the column A.CONTRACT_NUMBER.

This is the code:

SELECT DISTINCT A.CONTRACT_NUMBER
, A.DTIME_SIGNATURE
, A.ID_CUID
, A.CLIENT_SEGMENT
, A.CLIENT_GENDER
, A.CLIENT_AGE
, A.CNT_SIGNED
, A.AMT_SIGNED
, A.INSTALMENTS
, A.PRODUCT
, B.AMT_INTEREST_INCOME
  FROM DM_SALES.V_SALES_DM_DATA A
  LEFT JOIN DM_FIN.FIN_LTV_DATAMART B ON A.CONTRACT_NUMBER = B.CONTRACT_NUMBER
  WHERE 1=1
  AND A.CONTRACT_STATE <> 'Cancelled' 
  AND a.cnt_signed=1 
  AND A.LOAN_TYPE = 'Consumer Loan'
  AND (TRUNC(A.DTIME_SIGNATURE) BETWEEN DATE'2022-08-01' AND DATE '2022-08-31')
  GROUP BY A.CONTRACT_NUMBER
  ORDER BY A.DTIME_SIGNATURE
;

It runs normally but after checking the data, there are still repeated values in the A.CONTRACT_NUMBER column. A.CONTRACT_NUMBER is like the primary key column and I'd like to select unique values to that column

Thanks: :D

Answer 1

Per contract you want the average interest income from your datamart table, so aggregate your datamart data by contract and join this result to your sales data.table.

SELECT
  sd.*,
  dm.avg_interest_income
FROM dm_sales.v_sales_dm_data sd
LEFT JOIN 
(
  SELECT contract_number, AVG(amt_interest_income) AS avg_interest_income
  FROM dm_fin.fin_ltv_datamart
  GROUP BY contract_number
) dm ON dm.contract_number = sd.contract_number
WHERE sd.contract_state <> 'Cancelled' 
  AND sd.cnt_signed = 1 
  AND sd.loan_type = 'Consumer Loan'
  AND sd.dtime_signature >= DATE '2022-08-01'
  AND sd.dtime_signature < DATE '2022-09-01'
ORDER BY sd.dtime_signature;