halligalli:

If you use DBI, then you can get the names and data types of the columns of a result set, and write the appropriate code to manipulate the data. For example, if you're writing a spreadsheet, you can find out if a column is varchar, float, date, or whatever, and use the correct Spreadsheet::WriteExcel write function to ensure that the data looks like you want it to.

Since your question lacks so many specifics, it's hard for me to give a better answer than that. Read the DBI docs, and give it a try. If you have any further questions after that, let us know...

...roboticus