我想知道为什么这个查询在不同版本的 MySQL 中显示不同的结果:
https://dbfiddle.uk/?rdbms=mysql_5.7&fiddle=409db6dd827acd7bda4ff9723fa108d9
在 MySQL 8 fiddle 中,不应显示从 10:00 到 10:30 的时段,因为表中有从 10:00 到 10:30 的约会。
MySQL 5.7:
CREATE TABLE shifts (
id int NOT NULL,
unique_id varchar(255) NOT NULL,
start_date DATETIME NOT NULL,
end_date DATETIME NOT NULL,
PRIMARY KEY (id)
);
CREATE TABLE appointments (
id int NOT NULL,
unique_id varchar(255) NOT NULL,
start_date DATETIME NOT NULL,
end_date DATETIME NOT NULL,
shift_id int NOT NULL,
PRIMARY KEY (id),
FOREIGN KEY (shift_id) REFERENCES shifts(id)
);
INSERT INTO `shifts` (`id`, `unique_id`, `start_date`, `end_date`)
VALUES
('4596', '614fc0c5dab2485bba8cbbd9eb98aa53', '2022-02-28 10:00:00', '2022-03-15 19:00:00');
INSERT INTO `appointments` (`id`, `unique_id`, `start_date`, `end_date`, `shift_id`)
VALUES
(18382, '1371e41a7cf342bfa279a8b120cc5f43', '2022-02-28 10:00:00', '2022-02-28 10:30:00', 4596),
(18517, '124baaa1aeab421cb288f2b7c7abe89b', '2022-02-28 10:30:00', '2022-02-28 11:00:00', 4596),
(18523, 'aff5abe6e8f84a64ace3277d3cd6dbd1', '2022-02-28 11:00:00', '2022-02-28 12:00:00', 4596),
(18355, 'ec570f9365bb4ad68c7b5ab3b7d9aeea', '2022-02-28 12:00:00', '2022-02-28 12:30:00', 4596),
(18537, 'e1946add03cd412da357b58c93d58c6e', '2022-02-28 12:30:00', '2022-02-28 13:15:00', 4596),
(18540, 'e16af8a053594e8b8340ede302398a22', '2022-02-28 13:30:00', '2022-02-28 14:00:00', 4596),
(18235, 'deac969701ae47f0a78696f12c267475', '2022-02-28 14:00:00', '2022-02-28 14:30:00', 4596),
(18462, '3270929ae6e546fb824e6d3219917b8e', '2022-02-28 14:30:00', '2022-02-28 16:00:00', 4596),
(18544, 'd27bc7ba34a74f078966ebe1567d3181', '2022-02-28 16:00:00', '2022-02-28 16:30:00', 4596),
(18622, '02ca48b35ca3462f9030bcb97ea1dbab', '2022-02-28 16:30:00', '2022-02-28 16:50:00', 4596),
(18545, '4a49c054e59e4514ae2a521b55a7715c', '2022-02-28 16:50:00', '2022-02-28 17:15:00', 4596),
(18351, '6a0d56ad43894b60b4f8a289fbbfff73', '2022-02-28 17:30:00', '2022-02-28 18:15:00', 4596),
(18352, 'accdc12943954ee2bd69ad116c2fef3d', '2022-02-28 18:15:00', '2022-02-28 19:00:00', 4596);
SELECT Available_from, Available_to
FROM (
SELECT COALESCE(@lasttime_to, '2022-02-28 10:00:00') AS Available_from, start_date AS Available_to, @lasttime_to := end_date
FROM (SELECT start_date, end_date
FROM appointments
WHERE shift_id = 4596
AND end_date <= '2022-02-28 19:00:00'
AND start_date >= '2022-02-28 10:00:00'
UNION ALL (
SELECT '2022-02-28 19:00:00', '2022-02-28 19:00:00'
)
UNION ALL (
SELECT '2022-02-28 10:00:00', '2022-02-28 10:00:00'
)
ORDER BY start_date
) e
JOIN (SELECT @lasttime_to := NULL) init) x
WHERE Available_to > DATE_ADD(Available_from, INTERVAL 14 MINUTE);
结果:
Available_from Available_to
2022-02-28 13:15:00 2022-02-28 13:30:00
2022-02-28 17:30:00 2022-02-28 17:30:00
MySQL 8.0:
CREATE TABLE shifts (
id int NOT NULL,
unique_id varchar(255) NOT NULL,
start_date DATETIME NOT NULL,
end_date DATETIME NOT NULL,
PRIMARY KEY (id)
);
CREATE TABLE appointments (
id int NOT NULL,
unique_id varchar(255) NOT NULL,
start_date DATETIME NOT NULL,
end_date DATETIME NOT NULL,
shift_id int NOT NULL,
PRIMARY KEY (id),
FOREIGN KEY (shift_id) REFERENCES shifts(id)
);
INSERT INTO `shifts` (`id`, `unique_id`, `start_date`, `end_date`)
VALUES
('4596', '614fc0c5dab2485bba8cbbd9eb98aa53', '2022-02-28 10:00:00', '2022-03-15 19:00:00');
INSERT INTO `appointments` (`id`, `unique_id`, `start_date`, `end_date`, `shift_id`)
VALUES
(18382, '1371e41a7cf342bfa279a8b120cc5f43', '2022-02-28 10:00:00', '2022-02-28 10:30:00', 4596),
(18517, '124baaa1aeab421cb288f2b7c7abe89b', '2022-02-28 10:30:00', '2022-02-28 11:00:00', 4596),
(18523, 'aff5abe6e8f84a64ace3277d3cd6dbd1', '2022-02-28 11:00:00', '2022-02-28 12:00:00', 4596),
(18355, 'ec570f9365bb4ad68c7b5ab3b7d9aeea', '2022-02-28 12:00:00', '2022-02-28 12:30:00', 4596),
(18537, 'e1946add03cd412da357b58c93d58c6e', '2022-02-28 12:30:00', '2022-02-28 13:15:00', 4596),
(18540, 'e16af8a053594e8b8340ede302398a22', '2022-02-28 13:30:00', '2022-02-28 14:00:00', 4596),
(18235, 'deac969701ae47f0a78696f12c267475', '2022-02-28 14:00:00', '2022-02-28 14:30:00', 4596),
(18462, '3270929ae6e546fb824e6d3219917b8e', '2022-02-28 14:30:00', '2022-02-28 16:00:00', 4596),
(18544, 'd27bc7ba34a74f078966ebe1567d3181', '2022-02-28 16:00:00', '2022-02-28 16:30:00', 4596),
(18622, '02ca48b35ca3462f9030bcb97ea1dbab', '2022-02-28 16:30:00', '2022-02-28 16:50:00', 4596),
(18545, '4a49c054e59e4514ae2a521b55a7715c', '2022-02-28 16:50:00', '2022-02-28 17:15:00', 4596),
(18351, '6a0d56ad43894b60b4f8a289fbbfff73', '2022-02-28 17:30:00', '2022-02-28 18:15:00', 4596),
(18352, 'accdc12943954ee2bd69ad116c2fef3d', '2022-02-28 18:15:00', '2022-02-28 19:00:00', 4596);
SELECT Available_from, Available_to
FROM (
SELECT COALESCE(@lasttime_to, '2022-02-28 10:00:00') AS Available_from, start_date AS Available_to, @lasttime_to := end_date
FROM (SELECT start_date, end_date
FROM appointments
WHERE shift_id = 4596
AND end_date <= '2022-02-28 19:00:00'
AND start_date >= '2022-02-28 10:00:00'
UNION ALL (
SELECT '2022-02-28 19:00:00', '2022-02-28 19:00:00'
)
UNION ALL (
SELECT '2022-02-28 10:00:00', '2022-02-28 10:00:00'
)
ORDER BY start_date
) e
JOIN (SELECT @lasttime_to := NULL) init) x
WHERE Available_to > DATE_ADD(Available_from, INTERVAL 14 MINUTE);
结果:
Available_from Available_to
2022-02-28 10:00:00 2022-02-28 10:30:00
2022-02-28 13:15:00 2022-02-28 13:30:00
2022-02-28 17:15:00 2022-02-28 17:30:00
最佳答案
您的子查询 e
按 start_date
排序,这是不确定的,因为可能有几行具有相同的值。
使用 MySQL 5.7:
- 此子查询的第一行是您通过
union
创建的假查询。它的from_date
是2022-02-28 10:00:00
而它的end_date
是2022-02-28 10:00: 00
,这将成为下一行的Available_from
,因为您使用了@lasttime_to
进行查询。 - 下一行是与约会 18382 相关的行,它变为“从 2022-02-28 10:00:00 到 2022-02-28 10:00:00”,并设置了
end_date
到2022-02-28 10:30:00
,这将是下一行的Available_from
。 - 下一行是与约会 18517 相关的行,它变为“从 2022-02-28 10:30:00 到 2022-02-28 10:30:00”
所以在这里,这 3 行都不符合条件 Available_to > DATE_ADD(Available_from, INTERVAL 14 MINUTE);
使用 MySQL 8:
- 此子查询的第一行与约会 18382 相关,而不是假的。它的
from_date
是2022-02-28 10:00:00
而它的end_date
是2022-02-28 10:30: 00
,这将成为下一行的Available_from
,因为您使用了@lasttime_to
进行查询。 - 下一行是您通过
union
创建的伪造的。它变为“2022-02-28 10:30:00 2022-02-28 10:00:00”(!),其end_date
为2022-02-28 10:00 :00
,这将是下一行的Available_from
。 - 下一行是与约会 18517 相关的行,变为“2022-02-28 10:00:00 到 2022-02-28 10:30:00”。
在这里,第三行符合条件 Available_to > DATE_ADD(Available_from, INTERVAL 14 MINUTE);
,这就是为什么你会得到额外的一行。
TL;DR:行的 Available_from
值依赖于子查询 e
获得的非确定性顺序。然后,您的结果在引擎之间不一致。
关于mysql - 结果差异(MySQL 5.7 与 MySQL 8.0),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/71209235/