Postgres 将查询结果同时插入数据表

INSERT INTO table [ ( column [, ...] ) ]
 { DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) [, ...] | query }
 [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]

INSERT INTO SELECT 可以将 select 的结果集同时插入到另一个指定的表中，大大提高了效率，如下：

INSERT INTO
    widgets
    (
        map_id,
        widget_name
    )
SELECT
   mt.map_id,
   'Bupo'
FROM
    map_tags mt
WHERE
    mt.map_license = ''

INSERT INTO blog_sums ( blog_id, date, total_comments)
    SELECT blog_id, '2016-09-22', count(comment_id) as total_comments_update
    FROM blog_comments
    WHERE date = '2016-09-22'
    GROUP BY blog_id
ON CONFLICT (blog_id ,date)
DO UPDATE SET total_comments = excluded.total_comments;