Teradata Get MTD Unique Users for each day (ex. on 12th Mar I need to have 1st to 12th unique users. similarly for each date for last one year

Question

I need to get MTD Unique users count each day for last 1 year. Ex. if my data is like

dt  customername
1   a
1   b
2   a
2   c
3   b
3   a
4   c
4   d
4   e

expected output- on 1st only 2 unique user. on 2nd (1&2nd) 3 users. on 3rd (1st to 3rd) 3 users. on 4th (1st to 4th) 5 users. I need this for each month for each date for last 1 year

dt uniquecustcount
1  2
2  3
3  3
4  5

my data is in below format, bu core logic is above one for MTD. Appreciate any help please

CREATE MULTISET TABLE GK_DAILY_USERS ,NO FALLBACK ,
     NO BEFORE JOURNAL,
     NO AFTER JOURNAL,
     CHECKSUM = DEFAULT,
     DEFAULT MERGEBLOCKRATIO
     (
      EVENT_DATE DATE FORMAT 'yyyy-mm-dd',
      Subs_Id INTEGER,
      PAYMENT_METHOD_CD VARCHAR(8) CHARACTER SET UNICODE NOT CASESPECIFIC,
      Data_User_Flag VARCHAR(1) CHARACTER SET UNICODE NOT CASESPECIFIC,
      BUS_UNIT VARCHAR(20) CHARACTER SET LATIN NOT CASESPECIFIC,
      Event_Count INTEGER)
PRIMARY INDEX ( EVENT_DATE ,Subs_Id );

Insert into GK_DAILY_USERS values (?,?,?,?,?,?);

I am trying below sql. I know this sql doesnt make sense and hence looking for solution.

SELECT EVENT_DATE, MAX(R2) FROM (
SELECT EVENT_DATE 
,COUNT(A.SUBS_ID)OVER(ORDER BY ROWNUM,A.SUBS_ID) AS R2
FROM (
SELECT A.EVENT_DATE,A.SUBS_ID
,Row_Number() Over (Order by EVENT_DATE, SUBS_ID) rownum
,COUNT(A.SUBS_ID)OVER(PARTITION BY A.SUBS_ID ORDER BY A.EVENT_DATE) AS RUN_TOTAL3
FROM  GK_DAILY_USERS A 
WHERE Data_User_Flag='Y' 
AND subs_id in (566875703,289813839, 151153086,279262050,18378517)
ORDER BY EVENT_DATE, SUBS_ID
) A 
WHERE RUN_TOTAL3 = 1
) A GROUP BY EVENT_DATE ORDER BY 1
;

Answer 1

SELECT EVENT_DATE 
   -- new customers per date
  ,Sum(SUBS_ID) AS daily_new_cust
  -- running total of new customers per date
  ,Sum(Sum(SUBS_ID))
   Over(ORDER BY EVENT_DATE
        ROWS Unbounded Preceding) AS unique_cust
FROM
 (
   SELECT *
   FROM  GK_DAILY_USERS
   WHERE Data_User_Flag='Y' 
   AND subs_id IN (566875703,289813839, 151153086,279262050,18378517)
   QUALIFY
      -- return a single row with the earliest date for each subs_id
      Row_Number()
      Over (PARTITION BY A.SUBS_ID
            ORDER BY EVENT_DATE) = 1
 ) AS dt
GROUP BY EVENT_DATE 
ORDER BY 1
;