CREATE TABLE IF NOT EXISTS `maf_game_questions` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`gid` int(11) NOT NULL,
`qid` int(11) NOT NULL,
`qtext` text NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB ;
INSERT INTO `maf_game_questions` (`id`, `gid`, `qid`, `qtext`) VALUES
(1, 1, 6, 'Click on a state that has part of the Rocky Mountain Range to reveal a fact about agriculture.'),
(2, 1, 1, 'Click on a state that borders another country to see a fact about agriculture.'),
(3, 1, 15, 'Find a state where part of the border is created by a river to show a fact about agriculture.'),
(4, 1, 14, 'Choose a state that has part of the Missouri River to see a fact about agriculture.'),
(5, 1, 5, 'Click on a state that borders the Mississippi river to see a fact about agriculture.'),
(6, 1, 16, 'Click on a state with a panhandle to see a fact about agriculture.'),
(7, 1, 8, 'Find a state that is part of the Great Plains to check out a fact about agriculture.'),
(8, 1, 3, 'Select a state that has a bay to show a fact about agriculture.'),
(9, 1, 13, 'Select a state that has part of the Ohio River to view a fact about agriculture.'),
(10, 1, 9, 'Choose a state that is on the Atlantic Ocean to reveal a fact about agriculture.'),
(11, 1, 10, 'Select a state on the Pacific Ocean to see a fact about agriculture.'),
(12, 1, 4, 'Choose a state on the Gulf of Mexico to show a fact about agriculture.'),
(13, 1, 7, 'Find a state that has part of the Appalachian Mountain Range to see a fact about agriculture.'),
(14, 1, 2, 'Find a state that has a peninsula to check out a fact about agriculture.'),
(15, 1, 11, 'Click on a state with a desert to show a fact about agriculture.'),
(16, 1, 12, 'Find a state that borders one of the Great Lakes to see a fact about agriculture.');
CREATE TABLE IF NOT EXISTS `maf_game_stats` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`userid` varchar(100) NOT NULL,
`sessionid` varchar(100) NOT NULL,
`gid` int(11) NOT NULL,
`qid` int(11) NOT NULL,
`result` varchar(50) NOT NULL,
`accesstime` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB;
INSERT INTO `maf_game_stats` (`id`, `userid`, `sessionid`, `gid`, `qid`, `result`, `accesstime`) VALUES
(1, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 6, '0', '2013-04-02 16:26:22'),
(2, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 1, '1', '2013-04-02 16:26:27'),
(3, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 15, '0', '2013-04-02 16:26:35'),
(4, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 14, '1', '2013-04-02 16:26:42'),
(5, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 5, '1', '2013-04-02 16:26:51'),
(6, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 6, '1', '2013-04-04 16:27:24'),
(7, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 16, '1', '2013-04-04 16:27:32'),
(8, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 15, '0', '2013-04-04 16:27:38'),
(9, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 8, '1', '2013-04-04 16:27:48'),
(10, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 3, '1', '2013-04-02 16:31:22'),
(11, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 16, '1', '2013-04-02 16:31:28'),
(12, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 13, '0', '2013-04-02 16:31:44'),
(13, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 9, '0', '2013-04-02 16:31:53'),
(14, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 8, '1', '2013-04-02 16:32:00'),
(15, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 16, '1', '2013-04-02 16:35:02'),
(16, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 10, '0', '2013-04-02 16:35:11'),
(17, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 4, '0', '2013-04-02 16:35:17'),
(18, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 9, '1', '2013-04-02 16:35:23'),
(19, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 4, '0', '2013-04-02 16:35:29'),
(20, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 7, '0', '2013-04-03 19:06:12'),
(21, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 2, '1', '2013-04-03 19:06:17'),
(22, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 11, '0', '2013-04-03 19:06:29'),
(23, 'KIHYAKQTZLSB975', 'ccb4vm744cttrc8is1uuosf8e0', 1, 12, '0', '2013-04-03 19:06:33'),
(24, 'KIHYAKQTZLSB975', 'r0ci652ln8j1oqhvjd88s0is34', 1, 5, '0', '2013-04-05 09:47:22'),
(25, 'KIHYAKQTZLSB975', 'r0ci652ln8j1oqhvjd88s0is34', 1, 2, '1', '2013-04-05 09:47:28'),
(26, 'KIHYAKQTZLSB975', 'r0ci652ln8j1oqhvjd88s0is34', 1, 14, '0', '2013-04-05 09:47:37'),
(27, 'KIHYAKQTZLSB975', 'r0ci652ln8j1oqhvjd88s0is34', 1, 9, '1', '2013-04-05 09:47:43'),
(28, 'KIHYAKQTZLSB975', 'r0ci652ln8j1oqhvjd88s0is34', 1, 12, '0', '2013-04-05 09:47:50');
SELECT a.gid, a.qid, q.qtext, SUM(a.result = 1) first_attempt_correct, SUM(a.result = 0) first_attempt_incorrect, c.all_attempt_correct, c.all_attempt_incorrect
FROM maf_game_stats a
INNER JOIN
(
SELECT USERID, gid, QID, MIN(ACCESSTIME) AS min_date
FROM maf_game_stats
GROUP BY USERID, gid, qid
) b ON a.USERID = b.USERID AND
a.gid = b.gid AND
a.qid = b.qid AND
a.ACCESSTIME = b.min_date
INNER JOIN
(
SELECT gid, QID, SUM(result = 1) AS all_attempt_correct, SUM(result = 0) AS all_attempt_incorrect
FROM maf_game_stats
GROUP BY gid, qid
) c ON a.gid = c.gid AND
a.qid = c.qid
INNER JOIN maf_game_questions q ON a.qid = q.qid AND a.gid = q.gid
WHERE a.gid ='1'
AND a.ACCESSTIME >= '2013-04-05' AND a.ACCESSTIME < '2013-04-05' + INTERVAL 1 DAY
GROUP BY a.gid, a.qid
问：使用2013-04-02至2013-04-05的给定结果集下方的结果是否合理，但2013-04-05至2013-04-05当天没有结果？请问任何想法 这是sqlfidler：
http://sqlfiddle.com/#!2/181a2/1
------------------------ qtext 1st attempt correct 1st attempt incorrect all attempt correct all attempt incorrect ---------- --------------------- ---------------------- -------------------- --------------------------- question 0 0 0 1 question 0 0 0 1 question 0 0 0 0 question 0 0 0 0 question 0 0 1 0
答案 0 :(得分：0)
这就是您要找的 - 将WHERE条件移至您的JOIN。上述查询的问题是您加入了MIN(AccessTime)，并且在MIN结果中没有记录2013-04-05。
SELECT *
FROM maf_game_stats a
INNER JOIN
(
SELECT USERID, gid, QID, MIN(ACCESSTIME) AS min_date
FROM maf_game_stats
WHERE ACCESSTIME >= '2013-04-05' AND ACCESSTIME < '2013-04-06'
GROUP BY USERID, gid, qid
) b ON a.USERID = b.USERID AND
a.gid = b.gid AND
a.qid = b.qid AND
a.ACCESSTIME = b.min_date
INNER JOIN
(
SELECT gid, QID, SUM(result = 1) AS all_attempt_correct, SUM(result = 0) AS all_attempt_incorrect
FROM maf_game_stats
GROUP BY gid, qid
) c ON a.gid = c.gid AND
a.qid = c.qid
INNER JOIN maf_game_questions q ON a.qid = q.qid AND a.gid = q.gid
WHERE a.gid ='1'
GROUP BY a.gid, a.qid