Validating via an SQL Procedure Source Code

create procedure mrcworklib.validdates
(inout i_error char(99),
 inout i_strdate decimal(8,0),
 inout i_enddate decimal(8,0))
LANGUAGE SQL
CASE
when i_strdate = 0 and i_enddate = 0 then
   set i_error = 'You have not entered any dates.';
when i_strdate = 0 then
   set i_error = 'You must enter a starting date.';
when i_enddate = 0 then
   set i_error = 'You must enter an ending date.';
when i_strdate > i_enddate then
   set i_error = 'Start date is later than end date.';
else
   set i_error = ' ';
END CASE