1 -MYSQL: Выберите измененная строка, где
create table changes(snapdate date,value int, uid int);
insert into changes values
('2013-04-22', 0, 1),
('2013-04-21', 1,1),
('2013-04-20', 1,1),
('2013-04-19', 1,1),
('2013-04-19', 0,2),
('2013-04-19', 1,1),
('2013-04-18', 0,1),
('2013-04-17', 0,1),
('2013-04-17', 1,2),
('2013-04-16', 1,1),
('2013-04-16', 0 ,2);
2 -
SELECT a.snapdate, a.value
FROM (
SELECT t1.*, COUNT(*) AS rank
FROM changes t1
LEFT JOIN changes t2 ON t1.snapdate >= t2.snapdate
GROUP BY t1.snapdate
) AS a
LEFT JOIN (
SELECT t1.*, COUNT(*) AS rank
FROM changes t1
LEFT JOIN changes t2 ON t1.snapdate >= t2.snapdate
GROUP BY t1.snapdate
) AS b ON a.rank = b.rank+1 AND a.value = b.value
WHERE b.snapdate IS NULL
ORDER BY a.snapdate DESC;
работает нормально, но как выбрать WHERE uid=2
, например? я не могу использовать временную таблицу:
create temporary table changes_temp
as
select *
from changes
where uid = 2
http://dev.mysql.com/doc/refman/5.0/en/temporary-table-problems.html
Всего одно слово ==> PERFECT – OlZ
http://stackoverflow.com/questions/17085069/mysql-select-changed-row – OlZ