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SELECT executes one of several statement blocks depending on the value
of an expression.
 
SELECT CASE testexpression
CASE expressionlist1
  [statementblock-1]
[CASE expressionlist2
  [statementblock-2]] ...
[CASE ELSE
  [statementblock-n]]
END SELECT
 
     ■ The argument expressionlist can have any of these forms:
 
         expression[,expression]...
         expression TO expression
         IS relational-operator expression
 
         The following list describes the parts of expressionlist:
 
           expression           Any numeric or string expression. The type
                                of the expression must be compatible with
                                testexpression. (The type of expression
                                will be coerced to the same type as
                                testexpression. For example, if test-
                                expression is an integer, expressionlist
                                can contain a double-precision data
                                type.)
           relational-operator  <     Less than
                                <=    Less than or equal to
                                >     Greater than
                                >=    Greater than or equal to
                                <>    Not equal to
                                =     Equal to
 
Usage Notes
    ■ If testexpression matches the expressionlist associated with a
      particular CASE clause, the statement block following that CASE
      clause is executed up to the next CASE clause or, for the last one,
      up to END SELECT. Control then passes to the statement following
      END SELECT.
    ■ If you use the TO keyword to indicate a range of values, the smaller
      value must appear first. For example, the statements associated with
      the line:
 
         CASE -1 TO -5
 
      are not executed if the testexpresssion is -4. The line should be
      written as:
 
         CASE -5 TO -1
 
    ■ You can use a relational operator only if the IS keyword appears.
      If CASE ELSE is used, its associated statements are executed only if
      the testexpression does not match any of the other CASE selections.
      It is a good idea to have a CASE ELSE statement in your SELECT CASE
      block to handle unforeseen testexpression values.
    ■ When there is no CASE ELSE statement, and no expression listed in the
      CASE clauses matches testexpression, program execution continues
      normally.
    ■ You can use multiple expressions or ranges in each CASE clause. For
      example, the following line is valid:
 
         CASE 1 TO 4, 7 TO 9, 11, 13, IS > MaxNumber%
 
    ■ You can also specify ranges and multiple expressions for strings:
 
         CASE "everything", "nuts" TO "soup", TestItem$
 
      CASE matches strings that are exactly equal to everything, the
      current value of TestItem$, or that fall between nuts and soup in
      alphabetical order.
    ■ Strings are evaluated according to the ASCII values of their
      characters. Lowercase letters have larger ASCII values than
      uppercase, so this statement is true:
 
         nuts > Nuts > NUTS
 
    ■ If an expression appears in more than one CASE clause, only the
      statements associated with the first appearance of the expression are
      executed.
    ■ SELECT CASE statements can be nested. Each SELECT CASE statement must
      have a matching END SELECT statement.