"global" is indeed a postgres keyword
refer Postgres User's Guide Chapter 2-"SQL Syntax" in the section Key
words".
The following section gives the answer
The following are Postgres reserved words which are also SQL92 or SQL3
reserved words, and which are allowed to be present as column labels, but
not as identifiers:
On Wed, 23 Aug 2000, Dave Smith wrote:
CASE COALESCE CROSS CURRENT ELSE END FALSE FOREIGN GLOBAL GROUP LOCAL
NULLIF ORDER POSITION PRECISION TABLE THEN TRANSACTION TRUE
WHEN
Regards Sridhar