https://www.postgresql.org/docs/12/sql-createstatistics.html contains
this example command:
CREATE STATISTICS s2 (mcv) ON (a, b) FROM t2;
But that produces:
psql: ERROR: only simple column references are allowed in CREATE STATISTICS
I think the parentheses around (a, b) just need to be removed.
P.S. I think the fact that we print "psql: " before the ERROR here is
useless clutter. We didn't do that in v11 and prior and I think we
should kill it with fire.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company