[solidsnack9000]

By distinguishing key words from table names and column names, uppercasing can improve readability, since SQL has such a flexible/variable grammar.

If we wrote:

    select(col1, col2, col3, ..., from=table_name, limit=5)

or something like that, it's obvious what are the intrinsics and what are the variable parts without knowing anything about select but for SQL you need to know all the "sentence patterns".