From The Document Foundation Wiki
    < Faq‎ | Calc

    How to retrieve the content of cells originating from other files

    You can:

    1. open the source file;
    2. select and copy the desired cell(s) to the clipboard with CTRL + C;
    3. open the target file;
    4. choose the target cell;
    5. Go to Edit ▸ Paste special
    6. Select the Paste option.

    Or you can do this more directly by writing the following formula directly into the formula bar or into the target cell:


    For example :

    =DDE("soffice";"C:\My Documents\LibreOffice\MyFile.ods";"Sheet.A1")