Spreadsheets often have a very-ridiculous number of columns because it is easiest for a macro to work with one row of the sheet at a time, without resorting to VLOOKUP() and other such rot.   Even though the sheet contents are often the product of a fairly substantial database JOIN, you often do not have access to the original database from when the spreadsheet ultimately came.   What I usually suggest, in cases like this, is that you should try to avoid writing programs just to get your data into the thing, and that if possible you should do further manipulations by stored-procedure within the database environment.   Something equivalent to LOAD DATA INFILE usually exists somewhere, and the table which this loads into ought to basically be just a “holding tank.”   Then, additional queries can be run to, in effect, “un-join” the data and use it to update the permanent tables.   You may or may not use Perl, as the case may be, to do this.