Use the option paste Special (Special Paste) > Skip blanks (Ignore blank cells) and Excel will not fill existing values with blank cells.
- Select a range of cells B1: B12.
- Right click and click Copy (Copy).
- Highlight a cell A1.
- Right click and then select paste Special (Special insert).
- Enable the option Skip blanks (Ignore empty cells).
- Нажмите кнопку OK.