How do I merge cells within a table to create a label that spans several columns?

ThunderDog 

In an official Excel Table --- the kind that auto-formats the rows with alternating colors, etc.,--you aren't allowed to do what you're trying to do. It violates the whole purpose of the table, interferes with what Tables like that were created to do.

So let's back up...think of an Excel Table as the input end of things: it's where you store data, well organized data, clearly defined columns, rows of entries that describe something in consistent fashion, from row to row. Design a table well, but think of it solely or primarily as the input, the storage place for your raw data.

When it comes to nicely arranging things--doing something like, oh, merging cells within several of those columns so as to create a heading for several columns--then you're thinking output. And if you are doing summaries of the data in your Table, or extracting subsets based on criteria...then let's talk about how to do that as a second step, after you've entered everything into the Table.

But don't confuse the input with output. Excel has wonderful tools for extracting data from an Excel Table (input) and presenting those extracts in summary form or subsets of the whole that meet certain criteria or....in short, various kinds of output.

Now, if you really are just using Excel because it has rows and columns and you want to make some entries in cells and have it look neat for a presentation--i.e., if you're using Excel solely for its rows and columns but not for any kind of data manipulation--then just don't create the array as an Excel Table.