Comparision of a row with multiple criteria

Question

Hi All,
I have below source table which gives me CUTSOMER_ID, FIRST_NAME, LAST_NAME, DOB, ZIPCODE and D_ID. Now i need to compare it with target, which gives me same columns. below are my comparision criteria.
1. Compare CUSTOMER_ID, if it matches with any of the target CUSTOMER_ID mark the row with F_FLG = M
2. If CUSTOMER_ID does not match, then compare the row with target based on compbination of (FIRST_NAME, LAST_NAME, DOB and ZIPCODE). If this combination of columns matches with any of the row from target, then marked row with F_FLG = M
3. If CUSTOMER_ID and combination of (FIRST_NAME, LAST_NAME, DOB and ZIPCODE) column does not match with any of the target row, the use another set of column. compare the row with target based on compabination of (FIST_NAME, LAST_NAME, D_ID). If this combinatio of column matches with ay of the row from target, then marked row with F_FLG = M
4. If any of the above criteria does not match, then mark the row with F_FLG = N
CUSTOMER_ID     FIRST_NAME     LAST_NAME     DOB          ZIPCODE          D_ID
101          GEORGE          MAC          15-APRIL-2009     12345          23456
102          MICLE          DON          10-MARCH-1980     45678          29087
103          VIJAG          UJIK          01-JAN-1950     67890          27689
104          BONY          PANDA          03-MAY-1961     12345          27878These combinations should be performed once at a time. If it satisfies the first criteria, we do not need to check for remaining 3. If it does not match with 1 then perform 2 if matches flag the row and if not, go for 3rd criteria. if matches them mark with M else N
Below is the Target rows.
CUSTOMER_ID     FIRST_NAME     LAST_NAME     DOB          ZIPCODE          D_ID
101          ADA          MICO          15-APRIL-2009     12345          23456
999          MICLE          DON          10-MARCH-1980     45678          23567
888          VIJAG          UJIK          01-APR-1999     89897          27689
777          AAA          BBB          03-MAY-1961     87687          12345Here,
for 1st row, CUSTOMER_ID matches with source and target, flag the row with valye = M
for 2nd row, CUSTOMER_ID (102) does not match with Target. but combination of (FIRST_NAME, LAST_NAME, DOB and ZIPCODE) matches, flag the row with value = M
for 3rd row, CUSTOMER_ID (103) and combination of (FIRST_NAME, LAST_NAME, DOB and ZIPCODE) does not match, but combination of (FIRST_NAME, LAST_NAME and D_ID) matches, flag the row with value = M
for 4th row, none of the combination matches with Target, flag the row with value = N
Output should be
CUSTOMER_ID     FIRST_NAME     LAST_NAME     DOB          ZIPCODE          D_ID     F_FLG
101          GEORGE          MAC          15-APRIL-2009     12345          23456     M
102          MICLE          DON          10-MARCH-1980     45678          29087     M
103          VIJAG          UJIK          01-JAN-1950     67890          27689     M
104          BONY          PANDA          03-MAY-1961     12345          27878     N

Answer 1

Try this one
WITH data1 AS
     (SELECT 101 customer_id, 'GEORGE' first_name, 'MAC' last_name, TO_DATE ('15-APRIL-2009', 'dd-mon-yyyy') dob,
             12345 zipcode, 23456 d_id
        FROM DUAL
      UNION ALL
      SELECT 102 customer_id, 'MICLE' first_name, 'DON' last_name, TO_DATE ('10-MARCH-1980', 'dd-mon-yyyy') dob,
             45678 zipcode, 29087 d_id
        FROM DUAL
      UNION ALL
      SELECT 103 customer_id, 'VIJAG' first_name, 'UJIK' last_name, TO_DATE ('01-JAN-1950', 'dd-mon-yyyy') dob,
             67890 zipcode, 27689 d_id
        FROM DUAL
      UNION ALL
      SELECT 104 customer_id, 'BONY' first_name, 'PANDA' last_name, TO_DATE ('03-MAY-1961', 'dd-mon-yyyy') dob,
             12345 zipcode, 27878 d_id
        FROM DUAL),
     data2 AS
     (SELECT 101 customer_id, 'ADA' first_name, 'MICO' last_name, TO_DATE ('15-APRIL-2009', 'dd-mon-yyyy') dob,
             12345 zipcode, 23456 d_id
        FROM DUAL
      UNION ALL
      SELECT 999 customer_id, 'MICLE' first_name, 'DON' last_name, TO_DATE ('10-MARCH-1980', 'dd-mon-yyyy') dob,
             45678 zipcode, 23567 d_id
        FROM DUAL
      UNION ALL
      SELECT 888 customer_id, 'VIJAG' first_name, 'UJIK' last_name, TO_DATE ('01-APR-1999      ', 'dd-mon-yyyy') dob,
             89897 zipcode, 27689 d_id
        FROM DUAL
      UNION ALL
      SELECT 777 customer_id, 'AAA' first_name, 'BBB' last_name, TO_DATE ('03-MAY-1961      ', 'dd-mon-yyyy') dob,
             87687 zipcode, 12345 d_id
        FROM DUAL)
SELECT customer_id, first_name, last_name, dob, zipcode, d_id, f_flg
  FROM (SELECT customer_id, first_name, last_name, dob, zipcode, d_id, f_flg,
               ROW_NUMBER () OVER (PARTITION BY customer_id ORDER BY f_flg) rn
          FROM (SELECT DISTINCT d.customer_id, d.first_name, d.last_name, d.dob, d.zipcode, d.d_id,
                                CASE
                                   WHEN d.customer_id = d2.customer_id
                                      THEN 'M'
                                   WHEN d.first_name = d2.first_name
                                   AND d.last_name = d2.last_name
                                   AND d.dob = d2.dob
                                   AND d.zipcode = d2.zipcode
                                      THEN 'M'
                                   WHEN d.first_name = d2.first_name AND d.last_name = d2.last_name AND d.d_id = d2.d_id
                                      THEN 'M'
                                   ELSE 'N'
                                END f_flg
                           FROM data1 d, data2 d2
                       ORDER BY 1, DECODE (f_flg, 'M', 1)))
WHERE rn = 1Regards,
Mahesh Kaila