PostGreSql 生成連續的月

SELECT
to_char(b,'YYYY-MM') AS time
FROM
generate_series (to_timestamp ( '2018-01-01','YYYY-MM-DD hh24:mi:ss' ),to_timestamp ( '2018-12-07','YYYY-MM-DD hh24:mi:ss' ),'1 days' ) AS b
GROUP BY TIME order by time