Looks like it's sdata, maybe try something similar to 

 http://www.example.com/sdata/myApp/myContract/-/customers?where=name like '%BANK%'

Found from http://sage.github.io/SData-2.0/pages/core/0212/ which may be helpful here.

Replace the where with ----  "  &where=upper(BPCNAM)%20like%20%27J%25%27 "

JSeyler What does the %25 mean? and why is there only 1 %25?

the "%25" is Unicode for percent sign

 "  &where=upper(BPCNAM)%20like%20%27J%25%27 " is the same as  " &where=upper(BPCNAM) like 'J%' "