You can declare unions and structures, either directly or by using a type definition (typedef). You can use an element of a union as a host variable, but not the union as a whole. In contrast, a host variable can be either an entire structure or just one of the structure’s elements. The following example declares a union and a structure:
exec sql begin declare section;
typedef int PAYMENT_METHOD;
PAYMENT_METHOD method;
union salary_or_percentage {
CS_MONEY salary;
CS_NUMERIC percentage;
} amount;
struct employee_record {
char first_name[30];
char last_name[30];
char employee_ID[30];
} this_employee;
char *employee_of_the_month_ID = "01234567";
exec sql end declare section;
exec sql select first_name, last_name, employee_ID
into :this_employee
from employee_table
where employee_ID = :employee_of_the_month_ID;
exec sql select payment_type into :method
from remuneration_table where employee_ID =
:this_employee.employee_ID;
switch (method) {
case SALARIED:
exec sql select salary into
:amount.salary
from remuneration_table
where employee_ID =
this_employee.employee_ID;
break;
case VOLUNTEER:
exec sql select 0 into
:amount.salary
break;
case COMMISSION:
exec sql select commission_percentage into
:amount.percentage
from remuneration_table
where employee_ID =
this_employee.employee_ID;
break;
}
