有時(shí)候我們需要統(tǒng)計(jì)一段時(shí)間每天的數(shù)據(jù)仑撞，但數(shù)據(jù)表記錄中可能某些天并沒(méi)有記錄，想要用sql查出來(lái)凝垛，可以將如下生成的日期JOIN
SELECT
to_char( b, 'yyyy-mm-dd' ) AS TIME
FROM
generate_series (
to_timestamp( '2018-10-01', 'yyyy-mm-dd' ),
to_timestamp( '2018-10-07', 'yyyy-mm-dd' ),
'1 days'
) AS b
GROUP BY
TIME
ORDER BY
TIME
