Fix syntax in extract() examples
Fix syntax in extract() examples

Author: Erik Rijkers <602c57ffb51af99d6f3b54c0ee9587bb110fb990@xs4all.nl>

adam8157/gpdb,yazun/postgres-xl,lisakowen/gpdb,greenplum-db/gpdb,pavanvd/postgres-xl,ovr/postgres-xl,ovr/postgres-xl,greenplum-db/gpdb,50wu/gpdb,greenplum-db/gpdb,50wu/gpdb,snaga/postgres-xl,adam8157/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,xinzweb/gpdb,tpostgres-projects/tPostgres,Postgres-XL/Postgres-XL,ashwinstar/gpdb,xinzweb/gpdb,lisakowen/gpdb,techdragon/Postgres-XL,ashwinstar/gpdb,ashwinstar/gpdb,techdragon/Postgres-XL,ashwinstar/gpdb,arcivanov/postgres-xl,snaga/postgres-xl,zeroae/postgres-xl,lisakowen/gpdb,yazun/postgres-xl,snaga/postgres-xl,50wu/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,lisakowen/gpdb,jmcatamney/gpdb,lisakowen/gpdb,Postgres-XL/Postgres-XL,ovr/postgres-xl,greenplum-db/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,kmjungersen/PostgresXL,techdragon/Postgres-XL,oberstet/postgres-xl,postmind-net/postgres-xl,ovr/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,ashwinstar/gpdb,zeroae/postgres-xl,oberstet/postgres-xl,xinzweb/gpdb,zeroae/postgres-xl,yazun/postgres-xl,Postgres-XL/Postgres-XL,pavanvd/postgres-xl,jmcatamney/gpdb,tpostgres-projects/tPostgres,postmind-net/postgres-xl,ashwinstar/gpdb,postmind-net/postgres-xl,ashwinstar/gpdb,snaga/postgres-xl,ashwinstar/gpdb,oberstet/postgres-xl,kmjungersen/PostgresXL,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,xinzweb/gpdb,kmjungersen/PostgresXL,postmind-net/postgres-xl,greenplum-db/gpdb,tpostgres-projects/tPostgres,arcivanov/postgres-xl,kmjungersen/PostgresXL,tpostgres-projects/tPostgres,techdragon/Postgres-XL,ovr/postgres-xl,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,snaga/postgres-xl,adam8157/gpdb,arcivanov/postgres-xl,xinzweb/gpdb,pavanvd/postgres-xl,adam8157/gpdb,tpostgres-projects/tPostgres,xinzweb/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb,arcivanov/postgres-xl,50wu/gpdb,kmjungersen/PostgresXL,jmcatamney/gpdb,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,50wu/gpdb,pavanvd/postgres-xl,arcivanov/postgres-xl,yazun/postgres-xl,adam8157/gpdb,lisakowen/gpdb,jmcatamney/gpdb,lisakowen/gpdb,arcivanov/postgres-xl,oberstet/postgres-xl,yazun/postgres-xl