I have a table with football odds that looks like below:
You can do this by joining the table on itself:
select t_max.*, (t_max.H_odds - t_min.H_odds) as dif_h, (t_max.D_odds - t_min.D_odds) as dif_d, (t_max.A_odds - t_min.A_odds) as dif_a from ( select fixture_id, min(updated) min_updated, max(updated) max_updated from test group by fixture_id ) as t1 join test as t_min on (t_min.fixture_id = t1.fixture_id and t_min.updated = t1.min_updated) join test as t_max on (t_max.fixture_id = t1.fixture_id and t_max.updated = t1.max_updated)
In MySQL >= 8 there may be a solution using window-functions, but im not too sure about that since the fields you need can not be fetched by an aggregate function itself, they are just identified by an aggregate (namely
max) + fixture_id.
You'd need something like this:
SELECT MIN(updated) over (partition by fixture_id) ...
This get max updated for all grouped 'fixture_id' (but you dont want 'min(updated)', you want 'H_odds' etc. of the row having 'min(updated) AND fixture_id = "fixture_id of max(updated) with same fixture_id') - which, please correct me if im wrong, does not exist. But since you dont use MySql >= 8 anyways this is not an option.
And please get unique ids :)
You need to index your table:
// recommended if you plan to narrow down your results by this fields - which i assume create index t_f on test (fixture_id); create index t_u on test (updated); // MUST HAVE create unique index t_fu on test (fixture_id, updated);
If you dont do so, there will be temptables on your filesystem - (very very slow)
Update: A rather unpleasant MySQL >= 8 window-function version (using filesort - DO NOT USE).
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