'SQL' Case Statement Generator
Description
Includes built-in methods for generating long 'SQL' CASE statements,
and other 'SQL' statements that may otherwise be arduous to construct
by hand. The generated statement can easily be concatenated to string
literals to form queries to 'SQL'-like databases, such as when using
the 'RODBC' package. The current methods include casewhen() for building
CASE statements, inlist() for building IN statements, and
updatetable() for building UPDATE statements.