Deletes a variable definition from interactive and dynamic SQL
    that was used for invoking stored procedures and for testing
    procedures in modules or embedded SQL programs.

1  –  Environment

    You can use the UNDECLARE statement:

    o  In interactive SQL

    o  In dynamic SQL as a statement to be dynamically executed

2  –  Format

  UNDECLARE --+-> <variable-name> ------+--->
              +---------- , <-----------+

3  –  Arguments

3.1  –  variable-name

    Specifies the name of the local variables.

4  –  Example

    Example 1: Undeclaring variables in interactive SQL

    SQL> ATTACH 'FILENAME personnel';
    SQL>
    SQL> DECLARE :X INTEGER;
    SQL> DECLARE :Y CHAR(10);
    SQL>
    SQL> BEGIN
    cont>   SET :X = 100;
    cont>   SET :Y = 'Active';
    cont> END;
    SQL> PRINT :X, :Y;
               X   Y
             100   Active
    SQL> SHOW VARIABLES
    X                               INTEGER
    Y                               CHAR(10)
    SQL> UNDECLARE :X, :Y;