mysql 统计一天24小时数据默认补0SQL

mysql 统计一天24小时数据默认补0SQL

select a.click_date,ifnull(b.count,0) as count
from (
SELECT 0 as click_date
union all
SELECT 1 as click_date
union all
SELECT 2 as click_date
union all
SELECT 3 as click_date
union all
SELECT 4 as click_date
union all
SELECT 5 as click_date
union all
SELECT 6 as click_date
union all
SELECT 7 as click_date
union all
SELECT 8 as click_date
union all
SELECT 9 as click_date
union all
SELECT 10 as click_date
union all
SELECT 11 as click_date
union all
SELECT 12 as click_date
union all
SELECT 13 as click_date
union all
SELECT 14 as click_date
union all
SELECT 15 as click_date
union all
SELECT 16 as click_date
union all
SELECT 17 as click_date
union all
SELECT 18 as click_date
union all
SELECT 19 as click_date
union all
SELECT 20 as click_date
union all
SELECT 21 as click_date
union all
SELECT 22 as click_date
union all
SELECT 23 as click_date
) a left join (
SELECT
HOUR (login_time) AS hours,
sum(user_id) AS count
FROM
tb_log_login
WHERE
DATE_FORMAT(login_time, ‘%Y-%m-%d’) = DATE_FORMAT(‘2018-01-18’, ‘%Y-%m-%d’)
GROUP BY
hours
) b on a.click_date = b.hours;