为了让我的问题尽可能清楚（我之前因为太模糊而被呻吟），这里是我在项目中使用的两个表的结构和数据。 表1包含足球比赛列表，表2包含将记录在表1中的英国足球队。
我只是从我从图书馆拿出的一本书中学习SQL。我按照加入表格数据的说明进行操作。在这里，我只是尝试将数据回显到页面上，以确保在围绕此数据设置页面样式之前我的查询是正确的。
<?php
//Set DB Variables
$dbc = mysql_connect(host, username, password);
$db = mysql_select_db(database);
$results= mysql_query("SELECT 'tbl_games.game_ID', 'tbl_games.game_date', 'tbl_teams.team_name' FROM tbl_teams, tbl_games
WHERE 'tbl_games.team1_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team2_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team1_score' IS NULL AND 'tbl_games.team2_score' IS NULL");
while ($row = mysql_fetch_array($results)) {
foreach ($row as $columnName => $results) {
echo 'Column name: '.$columnName.' Column data: '.$columnData.'<br/>';
}
}
?>
运行代码时页面上没有打印错误，它只是不打印任何内容。但是（或者至少应该）会出现一些结果。我在这里弄错了什么？
--
-- Table structure for table `tbl_games`
--
DROP TABLE IF EXISTS `tbl_games`;
CREATE TABLE IF NOT EXISTS `tbl_games` (
`game_ID` int(6) NOT NULL AUTO_INCREMENT,
`team1_ID` int(4) NOT NULL,
`team2_ID` int(4) NOT NULL,
`team1_score` int(2) DEFAULT NULL,
`team2_score` int(2) DEFAULT NULL,
`game_date` date NOT NULL,
PRIMARY KEY (`game_ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=121 ;
--
-- Dumping data for table `tbl_games`
--
INSERT INTO `tbl_games` (`game_ID`, `team1_ID`, `team2_ID`, `team1_score`, `team2_score`, `game_date`) VALUES
(1, 42, 34, NULL, NULL, '2013-08-23'),
(2, 159, 45, NULL, NULL, '2013-08-23'),
(3, 5, 122, NULL, NULL, '2013-08-23'),
(4, 67, 12, NULL, NULL, '2013-08-24'),
(5, 60, 155, NULL, NULL, '2013-08-24'),
(6, 78, 105, NULL, NULL, '2013-08-24'),
(7, 101, 156, NULL, NULL, '2013-08-24'),
(8, 134, 144, NULL, NULL, '2013-08-24'),
(9, 142, 47, NULL, NULL, '2013-08-24'),
(10, 13, 88, NULL, NULL, '2013-08-24'),
(11, 21, 120, NULL, NULL, '2013-08-24'),
(12, 19, 16, NULL, NULL, '2013-08-24'),
(13, 20, 123, NULL, NULL, '2013-08-24'),
(14, 26, 29, NULL, NULL, '2013-08-24'),
(15, 36, 51, NULL, NULL, '2013-08-24'),
(16, 77, 21, NULL, NULL, '2013-08-24'),
(17, 81, 84, NULL, NULL, '2013-08-24'),
(18, 85, 18, NULL, NULL, '2013-08-24'),
(19, 132, 96, NULL, NULL, '2013-08-24'),
(20, 162, 50, NULL, NULL, '2013-08-24'),
(21, 22, 131, NULL, NULL, '2013-08-24'),
(22, 25, 152, NULL, NULL, '2013-08-24'),
(23, 86, 46, NULL, NULL, '2013-08-24'),
(24, 97, 27, NULL, NULL, '2013-08-24'),
(25, 107, 140, NULL, NULL, '2013-08-24'),
(26, 109, 115, NULL, NULL, '2013-08-24'),
(27, 127, 133, NULL, NULL, '2013-08-24'),
(28, 146, 69, NULL, NULL, '2013-08-24'),
(29, 150, 112, NULL, NULL, '2013-08-24'),
(30, 2, 38, NULL, NULL, '2013-08-24');
-- --------------------------------------------------------
--
-- Table structure for table `tbl_teams`
--
DROP TABLE IF EXISTS `tbl_teams`;
CREATE TABLE IF NOT EXISTS `tbl_teams` (
`team_ID` int(4) NOT NULL AUTO_INCREMENT,
`team_name` varchar(50) COLLATE latin1_general_ci NOT NULL,
PRIMARY KEY (`team_ID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=164 ;
--
-- Dumping data for table `tbl_teams`
--
INSERT INTO `tbl_teams` (`team_ID`, `team_name`) VALUES
(1, 'Aberdeen'),
(2, 'Accrington Stanley'),
(3, 'AFC Bournemouth'),
(4, 'AFC Wimbledon'),
(5, 'Airdrieonians'),
(6, 'Albion Rovers'),
(7, 'Aldershot Town'),
(8, 'Alfreton Town'),
(9, 'Alloa Athletic'),
(10, 'Annan Athletic'),
(11, 'Arbroath'),
(12, 'Arsenal'),
(13, 'Aston Villa'),
(14, 'Ayr United'),
(15, 'Barnet'),
(16, 'Barnsley'),
(17, 'Berwick Rangers'),
(18, 'Birmingham City'),
(19, 'Blackburn Rovers'),
(20, 'Blackpool'),
(21, 'Bolton Wanderers'),
(22, 'Bradford City'),
(23, 'Braintree Town'),
(24, 'Brechin City'),
(25, 'Brentford'),
(26, 'Brighton & Hove Albion'),
(27, 'Bristol City'),
(28, 'Bristol Rovers'),
(29, 'Burnley'),
(30, 'Burton Albion'),
(31, 'Bury'),
(32, 'Cambridge United'),
(33, 'Cardiff City'),
(34, 'Carlisle United'),
(35, 'Celtic'),
(36, 'Charlton Athletic'),
(37, 'Chelsea'),
(38, 'Cheltenham Town'),
(39, 'Chester'),
(40, 'Chesterfield'),
(41, 'Clyde'),
(42, 'Colchester United'),
(43, 'Coventry City'),
(44, 'Cowdenbeath'),
(45, 'Crawley Town'),
(46, 'Crewe Alexandra'),
(47, 'Crystal Palace'),
(48, 'Dagenham & Redbridge'),
(49, 'Dartford'),
(50, 'Derby County'),
(51, 'Doncaster Rovers'),
(52, 'Dumbarton'),
(53, 'Dundee'),
(54, 'Dundee United'),
(55, 'Dunfermline'),
(56, 'East Fife'),
(57, 'East Stirlingshire'),
(58, 'Elgin City'),
(59, 'England'),
(60, 'Everton'),
(61, 'Exeter City'),
(62, 'Falkirk'),
(63, 'FC Halifax Town'),
(64, 'Fleetwood Town'),
(65, 'Forest Green Rovers'),
(66, 'Forfar Athletic'),
(67, 'Fulham'),
(68, 'Gateshead'),
(69, 'Gillingham'),
(70, 'Greenock Morton'),
(71, 'Grimsby Town'),
(72, 'Hamilton Academical'),
(73, 'Hartlepool United'),
(74, 'Heart of Midlothian'),
(75, 'Hereford United'),
(76, 'Hibernian'),
(77, 'Huddersfield Town'),
(78, 'Hull City'),
(79, 'Hyde'),
(80, 'Inverness Caledonian Thistle'),
(81, 'Ipswich Town'),
(82, 'Kidderminster Harriers'),
(83, 'Kilmarnock'),
(84, 'Leeds United'),
(85, 'Leicester City'),
(86, 'Leyton Orient'),
(87, 'Lincoln City'),
(88, 'Liverpool'),
(89, 'Livingston'),
(90, 'Luton Town'),
(91, 'Macclesfield Town'),
(92, 'Manchester City'),
(93, 'Manchester United'),
(94, 'Mansfield Town'),
(95, 'Middlesbrough'),
(96, 'Millwall'),
(97, 'Milton Keynes Dons'),
(98, 'Montrose'),
(99, 'Morecambe'),
(100, 'Motherwell'),
(101, 'Newcastle United'),
(102, 'Newport County'),
(103, 'Northampton Town'),
(104, 'Northern Ireland'),
(105, 'Norwich City'),
(106, 'Nottingham Forest'),
(107, 'Notts County'),
(108, 'Nuneaton Town'),
(109, 'Oldham Athletic'),
(110, 'Oxford United'),
(111, 'Partick Thistle'),
(112, 'Peterborough United'),
(113, 'Peterhead'),
(114, 'Plymouth Argyle'),
(115, 'Port Vale'),
(116, 'Portsmouth'),
(117, 'Preston North End'),
(118, 'Queen of the South'),
(119, 'Queen''s Park'),
(120, 'Queens Park Rangers'),
(121, 'Raith Rovers'),
(122, 'Rangers'),
(123, 'Reading'),
(124, 'Republic of Ireland'),
(125, 'Rochdale'),
(126, 'Ross County'),
(127, 'Rotherham United'),
(128, 'Salisbury City'),
(129, 'Scotland'),
(130, 'Scunthorpe United'),
(131, 'Sheffield United'),
(132, 'Sheffield Wednesday'),
(133, 'Shrewsbury Town'),
(134, 'Southampton'),
(135, 'Southend United'),
(136, 'Southport'),
(137, 'St Johnstone'),
(138, 'St Mirren'),
(139, 'Stenhousemuir'),
(140, 'Stevenage'),
(141, 'Stirling Albion'),
(142, 'Stoke City'),
(143, 'Stranraer'),
(144, 'Sunderland'),
(145, 'Swansea City'),
(146, 'Swindon Town'),
(147, 'Tamworth'),
(148, 'Torquay United'),
(149, 'Tottenham Hotspur'),
(150, 'Tranmere Rovers'),
(151, 'Wales'),
(152, 'Walsall'),
(153, 'Watford'),
(154, 'Welling United'),
(155, 'West Bromwich Albion'),
(156, 'West Ham United'),
(157, 'Wigan Athletic'),
(158, 'Woking'),
(159, 'Wolverhampton Wanderers'),
(160, 'Wrexham'),
(161, 'Wycombe Wanderers'),
(162, 'Yeovil Town'),
(163, 'York City');
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
答案 0 :(得分：3)
查询中的单引号'（在PHP代码中）应该是反引号`，与创建表格的语句中的相同。
否则您在where子句中比较文字字符串，这些字符串不匹配。
另外，除非绝对必要，否则我不是真正喜欢使用反引号的粉丝。在我看来，它经常使SQL语句的可读性降低。它有它的位置，当然有些人可能更喜欢一致性而不是可读性，但我不是其中之一： - ）
但是，即使您解决了这个问题，您也会遇到问题：
WHERE tbl_games.team1_ID = tbl_teams.team_ID
AND tbl_games.team2_ID = tbl_teams.team_ID
因为你似乎要求所有那些球队对抗自己的比赛，这是我在很多体育比赛中都没有看到过的。
你需要重新思考你所要求的东西。例如，如果您只想要一个团队所有的游戏（作为团队1或团队2），您将使用OR而不是AND（并使用括号来确保正确混合AND / OR）。
答案 1 :(得分：0)
$results= mysql_query("SELECT 'tbl_games.game_ID', 'tbl_games.game_date', 'tbl_teams.team_name' FROM tbl_teams, tbl_games
WHERE 'tbl_games.team1_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team2_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team1_score' IS NULL AND 'tbl_games.team2_score' IS NULL");
应该是：
$results= mysql_query("SELECT `tbl_games`.`game_ID`, `tbl_games`.`game_date`, `tbl_teams`.`team_name` FROM tbl_teams, tbl_games
WHERE `tbl_games`.`team1_ID` = `tbl_teams`.`team_ID` AND `tbl_games`.`team2_ID` = `tbl_teams`.`team_ID` AND `tbl_games`.`team1_score` IS NULL AND `tbl_games`.`team2_score` IS NULL");
您使用了错误的引号，.不得在引号内。
由于您的表名或列名都不是保留字，因此您可以完全不使用引号：
$results= mysql_query("SELECT tbl_games.game_ID, tbl_games.game_date, tbl_teams.team_name FROM tbl_teams, tbl_games
WHERE tbl_games.team1_ID = tbl_teams.team_ID AND tbl_games.team2_ID = tbl_teams.team_ID AND tbl_games.team1_score IS NULL AND tbl_games.team2_score IS NULL");
我认为您可能需要的实际查询是：
SELECT tbl_games.game_ID, tbl_games.game_date, tbl_teams.team_name
FROM tbl_teams, tbl_games
WHERE (tbl_teams.team_ID = tbl_games.team1_ID AND tbl_games.team1_score IS NULL)
OR (tbl_teams.team_ID = tbl_games.team2_ID AND tbl_games.team2_score IS NULL)
这会找到每个团队计划玩的所有游戏，并且他们的分数为空。
答案 2 :(得分：0)
可能原因：它从2个表中选择数据（tbl_teams和tbl_games）
条件是tbl_teams.team_ID等于team2_ID 和 team1_ID。除非有双方同一支球队的比赛，否则这种情况永远不会奏效。
您没有指定查询返回的内容，因此我假设您只想要两个团队的结果。
你可能想要的是一个涉及3组数据的连接：游戏，第一个团队，第二个团队。在SQL中，这可以使用别名来完成。
试试这个：
SELECT tbl_games.game_ID,
tbl_games.game_date,
team1.team_name as "team1_name",
team2.team_name as "team2_name"
FROM
tbl_teams as team1,
tbl_teams as team2,
tbl_games
WHERE
tbl_games.team1_ID = team1.team_ID AND
tbl_games.team2_ID = team2.team_ID AND
tbl_games.team1_score IS NULL AND
tbl_games.team2_score IS NULL;
添加“is null”会减少结果。如果所有游戏都有分数，您将无法获得任何结果。
您的查询的另一个潜在问题是字段名称在单引号之间。我不确定在实际执行查询之前是否已通过php删除它们。如果他们不是，那就糟糕了;单引号之间的任何内容都被视为字符串。这意味着条件'tbl_games.team1_score' IS NULL实际上是将字符串'tbl_games.team1_score'与null进行比较而不是名为team1_score的字段的内容。
编辑：在where子句中添加了NULL，就像你有空值的示例数据一样。
答案 3 :(得分：0)
我认为您的查询存在问题'tbl_games.team1_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team2_ID' = 'tbl_teams.team_ID'。您正在将相同的ID与两个不同的字段进行比较tbl_games.team1_ID＆amp; tbl_games.team2_ID。
我认为tbl_games.team1_ID是一个与tbl_games.team2_ID对战的球队，意思是tbl_games.team1_ID != tbl_games.team2_ID。所以你只需要一个团队中的一个。
您的查询可能如下所示。
<?php
//Set DB Variables
$dbc = mysql_connect(host, username, password);
$db = mysql_select_db(database);
$results= mysql_query("SELECT tbl_games.game_ID, tbl_games.game_date, tbl_teams.team_name FROM tbl_teams, tbl_games
WHERE 'tbl_games.team1_ID' = 'tbl_teams.team_ID' AND 'tbl_games.team1_score' IS NULL AND 'tbl_games.team2_score' IS NULL");
while ($row = mysql_fetch_array($results)) {
foreach ($row as $columnName => $results) {
echo 'Column name: '.$columnName.' Column data: '.$columnData.'<br/>';
}
}
?>