DECODE(database_field, NULL, 'N','N','N','Y') = DECODE(incoming_param,'I', 'Y', 'E', 'N', 'A', 'Y' or 'A', 'N')
if incoming_param = 'I' then
'Y'
elsif incoming_param = 'E' then
'N'
elsif incoming_param = 'A' then
<I want the be able to capture a row if it is either 'Y' or 'N' when...