A reader from Bejing commented on a
recent post with
a question about data lengths and formats. While that wasn't really
related to my post, I thought I'd attempt to answer in a new entry,
here.
The question is basically this: when I combine two data sets with a
common-named column, why does the resulting data set seem to cut the
length short on the shared column?
Let's start with some definitions related to columns.