Mysql order by multiple columns with conditions-CodePudding

I have application using Mysql Database with this schema for example.

packages
id, name,       order
1, 'Free',      3
2, 'Basic',     2
3, 'Extensive', 1

ads
id,    date,                    package_id,   package_expires_at
1,     '2021-12-10 00:00:00',   1,            '2022-01-10'
2,     '2021-12-15 00:00:00',   3,            '2021-12-28'
3,     '2021-12-15 00:00:00',   3,            '2022-01-10'
4,     '2021-12-20 00:00:00',   2,            '2022-01-10'
5,     '2021-12-21 00:00:00',   1,            '2021-12-28'
6,     '2021-12-25 00:00:00',   1,            '2021-12-28'

What I need to achieve is selecting all ads but ordering none expired package first by packages.order asc, package_expire_at desc then order the expired by date desc

for example suppose we are in '2021-12-29' then the result should be

id,    date,                    package_id,   package_expires_at
3,     '2021-12-15 00:00:00',   3,            '2022-01-10'
4,     '2021-12-20 00:00:00',   2,            '2022-01-10'
1,     '2021-12-10 00:00:00',   1,            '2022-01-10'
6,     '2021-12-25 00:00:00',   1,            '2021-12-28'
5,     '2021-12-21 00:00:00',   1,            '2021-12-28'
2,     '2021-12-15 00:00:00',   3,            '2021-12-28'

I have added the schema on fiddle

http://sqlfiddle.com/#!9/cedb45/9

CodePudding user response：

The way you do this in (My)SQL is, you provide a virtual field as ORDER BY condition. Something like this should probably do the trick:

      SELECT a.id
           , a.date
           , a.package_id
           , a.package_expires_at
           , IF( a.package_expires_at < CURRENT_DATE,  1,         0                      ) AS is_expired
           , IF( a.package_expires_at < CURRENT_DATE,  a.`date`,  a.`package_expires_at` ) AS sort_date
           , p.`order`                                                                     AS sort_package_order
        FROM ads       AS  a
  INNER JOIN packages  AS  p 
          ON p.id = a.package_id
    ORDER BY IF( a.package_expires_at < CURRENT_DATE,  1,         0                      ) ASC
           , IF( a.package_expires_at < CURRENT_DATE,  1,         p.`order`              ) ASC
           , IF( a.package_expires_at < CURRENT_DATE,  a.`date`,  a.`package_expires_at` ) DESC

CodePudding user response：

use two separate query and then union them (your packages order is upside down of its ids now)

select * from (SELECT * from ads WHERE package_expires_at >= '2021-12-29' order by package_id asc, package_expires_at desc ) as a
union
select * from (SELECT * from ads WHERE package_expires_at < '2021-12-29' order by date desc) as b

if they are dynamic and without order, join them and then do things such as above .

select * from (SELECT ads.id,date,package_id,package_expires_at from ads left outer join packages on package_id = ads.id WHERE package_expires_at >= '2021-12-29' order by packages.order asc, package_expires_at desc ) as a
union
select * from ( SELECT ads.id,date,package_id,package_expires_at from ads left outer join packages on package_id = ads.id WHERE package_expires_at < '2021-12-29' order by date desc ) as b