Тhe customer id
get updated regularly. There is a table
that records this change.
Customer id, Customer’s Previous id, Customer’s Successor id
100,95,102
101,96,105
102,100,104
103,99,106
107,88,111
We need from this data for each customer id
, that latest changed customer id
. A sample of that from
above data would be:
Customer id, Latest Customer id
100,104
101,105
102,104
103,106
107,111
You can also use LEFT JOIN
if ID
is updated only once
SELECT A.CID,COALESCE(B.SCID,A.SCID) AS LCID
FROM #TABLEA A LEFT JOIN #TABLEA B ON A.CID=B.PCID
Output
+---------------+-------------------+
| Customer ID | Latest Customer id|
+---------------+-------------------+
| 100 | 104 |
| 101 | 105 |
| 102 | 104 |
| 103 | 106 |
| 107 | 111 |
+---------------+-------------------+
Note: Here I have refereed Customer ID as CID, Previous Customer ID as PCID & Successor Customer ID as SCID