Problem description

Excel data as shown:

We are trying to recode UNIQUE ID field. The rule is like this. Same IDs have same UNIQUE IDs. The expected result is the right part in the following table:

Solution

Use the SPL XLL plug-in of Excel

Write the formula in a blank cell:

As Shown:

Group A1’s data by ID, loop through each group to assign the current group number to variable a, and then loop through each record of the current group to assign a to UNIQUER ID.

Q & A Collection  

https://stackoverflow.com/questions/63797394/continuous-serial-number-generation-incl-duplicate-values