I have a column called "message" which has duplicate records in it. I want to create a new column named "serial" beside it to have a serial no. for the message.
If the first and second-row message columns are the same then the new column "serial" should have 1 and 1 in it. If not identical then it should have the serial number as 1 and 2, and continue the serial no. for other records based on the message column uniqueness.
Since my first two records has same value in message as arran I had the value as 1 for it wherever it appears in the table. If you see the message "flex" appears in different row but I consider the serial number as 2 wherever it appears.