I have a spreadsheet of over 15,000 lines of student information, sorted by student number. I want to count the number of rows which have a duplicate student number, up to 15 duplicates in a row, and show the total number of duplicates in a Separate Column. I.e.
Column 1 Column 2
Row 1 - 200101 3
Row 2 - 200101
Row 3 - 200101
Row 4 - 200102 2
Row 5 - 200102
Row 6 - 200103 1
I've been trying to use a Countif formula, but I found I had to use so many ANDs and ORs that the formula became too long. I don't know how to use programming code, only formulas in Excel. Is there an easier solution using some type of SUMPRODUCT code?
Column 1 Column 2
Row 1 - 200101 3
Row 2 - 200101
Row 3 - 200101
Row 4 - 200102 2
Row 5 - 200102
Row 6 - 200103 1
I've been trying to use a Countif formula, but I found I had to use so many ANDs and ORs that the formula became too long. I don't know how to use programming code, only formulas in Excel. Is there an easier solution using some type of SUMPRODUCT code?