sql - MariaDB - GROUP BY with an order -


so have dataset, order based on strings order field(field_name, ...) after order wan't group dataset based on column.

i have tried subquery, seems ignores order by when gets subqueried.

this query group group setting_id

select * `setting_values` ((`owned_by_type` = 'app\\models\\utecca\\user' , `owned_by_id` = 1 or ((`owned_by_type` = 'app\\models\\utecca\\agreement' , `owned_by_id` = 1006))) or (`owned_by_type` = 'app\\models\\utecca\\employee' , `owned_by_id` = 1)) , `setting_values`.`deleted_at` null order field(owned_by_type, 'app\\models\\utecca\\employee', 'app\\models\\utecca\\agreement', 'app\\models\\utecca\\user')

the order works fine, cannot group based on order, selects 1 lowest primary key (id).

here attempt did not work.

select * (     select *     `setting_values`     ((`owned_by_type` = 'app\\models\\utecca\\user' , `owned_by_id` = 1 or ((`owned_by_type` = 'app\\models\\utecca\\agreement' , `owned_by_id` = 1006))) or (`owned_by_type` = 'app\\models\\utecca\\employee' , `owned_by_id` = 1)) , `setting_values`.`deleted_at` null     order field(owned_by_type, 'app\\models\\utecca\\employee', 'app\\models\\utecca\\agreement', 'app\\models\\utecca\\user') ) t group setting_id;

here sample data enter image description here

what trying accomplish sample data 1 row id 3 row.
desired result set query should obey these rules

  • 1 row each setting_id
  • owned_by_type owned_by_id filtered following way agreement = 1006, user = 1, employee = 1.
  • when limiting 1 row each setting_idit should done following priority in owned_by_type column employee, agreement, user

here sqlfiddle it.

running mariadb version 10.2.6-mariadb

first of all, optimizer free ignore inner order by. so, please describe further intent is.

getting past that, can use subquery:

select ...     ( select             ...             group ...             order ...  -- lost unless followed :             limit 9999999999  -- valid; or high (for all)          ) x     group ...

perhaps doing groupwise max ??


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