passing REG_XML_COL as "rxml")
from STATE.CITY where ROW_TIME > CURRENT TIMESTAMP and HAVING(select COUNT (xmlquery('$cxml/Reg/Bus/External'
passing REG_XML_COL as "cxml")) >1 )
pretty sure a group by is required for a having clause.
Other than that, you didn't tell us that you were actually having a problem. Gave us a little on your requirements, didn't tell us what results you wanted from your specified data, didn't tell us what you are getting(wrong data/syntax error/a pat on the back)
Until we know any of that type info, there isn't much sense in us attempting to help you. Please try being a little more descriptive with your issue and what you want.