The reference pages for the if... else command includes this note, which is incomplete:
When a create
table or create view command occurs
within an if...else block, Adaptive Server creates
the schema for the table or view before determining whether the
condition is true. This may lead to errors if the table or view
already exists.
The note should read:
When an alter
table, create table, or create
view command occurs within an if...else block,
Adaptive Server creates the schema for the table or view before
determining whether the condition is true. This may lead to errors
if the table or view already exists.