How do I lookup for a field which has Or condition.
Source Destination File name
act bank indexes_%
bank act indices_% OR integer_%
OR does not work, should I use pipe character ?
Lookups don't implement boolean functions like that - they're just doing straightforward matching. You can optionally configure them to do wildcard matching or CIDR matching but that's it.
What you could do instead is to have separate lines in your lookup for the statements instead. Like this:
Note that in order for this to work, you need to configure the match_type to be WILDCARD(file_name) in the lookup definition in transforms.conf.