mysql内部连接与3表问题与订单计数

Question

我有以下示例表。

CREATE TABLE IF NOT EXISTS `my_customer` (
    `customer_id` int(11) NOT NULL AUTO_INCREMENT, 
    `customer_email` text NOT NULL, 
    PRIMARY KEY (`customer_id`) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=64 ; 

INSERT INTO `my_customer` (`customer_id`, `customer_email`) VALUES 
(4, 'muthu.d@test.in'), 
(5, 'nsrirengan@test.in'), 
(6, 'vinothini.k@test.in'), 
(8, 'vinothini.k111@test.in'), 
(63, 'sri.n321@test.in'), 
(56, 'vesri.n@test.in'), 
(57, 'veesri.n@test.in'), 
(58, 'veeisri.n@test.in'), 
(59, 'ren@test.in'), 
(60, 'ren1@test.in'), 
(61, 'nsrirengan123@test.in'), 
(62, 'nsrirengan321@test.in'), 
(53, 'sri.n@test.in'), 
(54, 'royalrenga@test.in'), 
(55, 'vesri@test.in'); 

CREATE TABLE IF NOT EXISTS `my_order` (
    `orderid` int(11) NOT NULL AUTO_INCREMENT, 
    `ordergenerateid` varchar(20) NOT NULL, 
    `restaurant_id` int(11) NOT NULL, 
    `customer_id` int(11) NOT NULL, 
    `usertype` varchar(10) NOT NULL, 
    `customeremail` varchar(200) NOT NULL, 
    PRIMARY KEY (`orderid`) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=152 ; 


INSERT INTO `my_order` (`orderid`, `ordergenerateid`, `restaurant_id`, `customer_id`, `usertype`, `customeremail`) VALUES 
(1, 'ORD0001', 3, 6, 'C', 'vinothini.k@test.in'), 
(2, 'ORD0002', 1, 6, 'C', 'vinothini.k@test.in'), 
(3, 'ORD0003', 3, 6, 'C', 'vinothini.k@test.in'), 
(4, 'ORD0004', 3, 6, 'C', 'vinothini.k@test.in'), 
(5, 'ORD0005', 3, 0, 'G', 'vinothini.k5555555@test.in'), 
(6, 'ORD0006', 3, 6, 'C', 'vinothini.k@test.in'), 
(7, 'ORD0007', 3, 6, 'C', 'vinothini.k@test.in'), 
(8, 'ORD0008', 3, 6, 'C', 'vinothini.k@test.in'), 
(9, 'ORD0009', 3, 6, 'C', 'vinothini.k@test.in'), 
(10, 'ORD0010', 3, 6, 'C', 'vinothini.k@test.in'), 
(11, 'ORD0011', 3, 6, 'C', 'vinothini.k@test.in'), 
(12, 'ORD0012', 3, 6, 'C', 'vinothini.k@test.in'), 
(13, 'ORD0013', 3, 6, 'C', 'vinothini.k@test.in'), 
(14, 'ORD0014', 3, 6, 'C', 'vinothini.k@test.in'), 
(15, 'ORD0015', 2, 3, 'C', 'sri.n@test.in'), 
(16, 'ORD0016', 2, 3, 'C', 'sri.n@test.in'), 
(17, 'ORD0017', 2, 3, 'C', 'sri.n@test.in'), 
(18, 'ORD0018', 2, 3, 'C', 'sri.n@test.in'), 
(19, 'ORD0019', 2, 3, 'C', 'sri.n@test.in'), 
(20, 'ORD0020', 8, 3, 'C', 'sri.n@test.in'), 
(21, 'ORD0021', 5, 3, 'C', 'sri.n@test.in'), 
(22, 'ORD0022', 13, 3, 'C', 'sri.n@test.in'), 
(23, 'ORD0023', 13, 3, 'C', 'sri.n@test.in'), 
(24, 'ORD0024', 13, 3, 'C', 'sri.n@test.in'), 
(25, 'ORD0025', 13, 3, 'C', 'sri.n@test.in'), 
(26, 'ORD0026', 13, 3, 'C', 'sri.n@test.in'), 
(27, 'ORD0027', 13, 3, 'C', 'sri.n@test.in'), 
(28, 'ORD0028', 13, 3, 'C', 'sri.n@test.in'), 
(29, 'ORD0029', 13, 3, 'C', 'sri.n@test.in'), 
(30, 'ORD0030', 13, 3, 'C', 'sri.n@test.in'), 
(31, 'ORD0031', 13, 3, 'C', 'sri.n@test.in'), 
(32, 'ORD0032', 13, 3, 'C', 'sri.n@test.in'), 
(33, 'ORD0033', 13, 3, 'C', 'sri.n@test.in'), 
(34, 'ORD0034', 13, 3, 'C', 'sri.n@test.in'), 
(35, 'ORD0035', 13, 3, 'C', 'sri.n@test.in'), 
(36, 'ORD0036', 13, 3, 'C', 'sri.n@test.in'), 
(37, 'ORD0037', 13, 3, 'C', 'sri.n@test.in'), 
(38, 'ORD0038', 13, 3, 'C', 'sri.n@test.in'), 
(39, 'ORD0039', 19, 3, 'C', 'sri.n@test.in'), 
(40, 'ORD0040', 13, 3, 'C', 'sri.n@test.in'), 
(41, 'ORD0041', 13, 3, 'C', 'sri.n@test.in'), 
(42, 'ORD0042', 13, 3, 'C', 'sri.n@test.in'), 
(43, 'ORD0043', 13, 3, 'C', 'sri.n@test.in'), 
(44, 'ORD0044', 13, 3, 'C', 'sri.n@test.in'), 
(45, 'ORD0045', 13, 3, 'C', 'sri.n@test.in'), 
(46, 'ORD0046', 13, 3, 'C', 'sri.n@test.in'), 
(47, 'ORD0047', 13, 3, 'C', 'sri.n@test.in'), 
(48, 'ORD0048', 13, 3, 'C', 'sri.n@test.in'), 
(49, 'ORD0049', 19, 3, 'C', 'sri.n@test.in'), 
(51, 'ORD0051', 13, 3, 'C', 'sri.n@test.in'), 
(52, 'ORD0052', 13, 3, 'C', 'sri.n@test.in'), 
(53, 'ORD0053', 13, 3, 'C', 'sri.n@test.in'), 
(54, 'ORD0054', 13, 10, 'G', 'sri.nas@test.in'), 
(55, 'ORD0055', 13, 11, 'G', 'sri.nasqw@test.in'), 
(56, 'ORD0056', 13, 12, 'G', 'sri.nqw@test.in'), 
(57, 'ORD0057', 13, 13, 'G', 'sri.nas1123@test.in'), 
(58, 'ORD0058', 13, 14, 'G', 'sri.nqw13@test.in'), 
(59, 'ORD0059', 13, 15, 'G', 'sri.nas123@test.in'), 
(60, 'ORD0060', 13, 16, 'G', 'sri.nas12345@test.in'), 
(61, 'ORD0061', 13, 17, 'G', 'sri.nqw123@test.in'), 
(62, 'ORD0062', 13, 18, 'G', 'sri.nas123111@test.in'), 
(63, 'ORD0063', 13, 19, 'G', 'sri@test.in'), 
(64, 'ORD0064', 13, 20, 'G', 'sri.nas111@test.in'), 
(65, 'ORD0065', 13, 21, 'G', 'sri.nas12354klk@test.in'), 
(66, 'ORD0066', 13, 22, 'G', 'sri.nas123879@test.in'), 
(67, 'ORD0067', 13, 23, 'G', 'sri.nasasd@test.in'), 
(68, 'ORD0068', 13, 24, 'G', 'sri.nasqwe@test.in'), 
(69, 'ORD0069', 13, 25, 'G', 'sri.nas121212@test.in'), 
(70, 'ORD0070', 13, 26, 'G', 'sri.nasqwqw@test.in'), 
(71, 'ORD0071', 13, 27, 'G', 'sri.nqw321@test.in'), 
(72, 'ORD0072', 13, 28, 'G', 'sri.nas123123@test.in'), 
(73, 'ORD0073', 13, 3, 'C', 'sri.n@test.in'), 
(74, 'ORD0074', 13, 3, 'C', 'sri.n@test.in'), 
(75, 'ORD0075', 13, 3, 'C', 'sri.n@test.in'), 
(76, 'ORD0076', 13, 3, 'C', 'sri.n@test.in'), 
(77, 'ORD0077', 13, 3, 'C', 'sri.n@test.in'), 
(78, 'ORD0078', 13, 3, 'C', 'sri.n@test.in'), 
(79, 'ORD0079', 13, 3, 'C', 'sri.n@test.in'), 
(121, 'ORD0121', 13, 52, 'G', 'sssri.n123123@test.in'), 
(122, 'ORD0122', 13, 3, 'C', 'sri.n@test.in'), 
(123, 'ORD0123', 13, 3, 'C', 'sri.n@test.in'), 
(84, 'ORD0084', 13, 3, 'C', 'sri.n@test.in'), 
(86, 'ORD0086', 13, 3, 'C', 'sri.n@test.in'), 
(87, 'ORD0087', 13, 3, 'C', 'sri.n@test.in'), 
(89, 'ORD0089', 13, 31, 'G', 'royalrenga@test.in'), 
(90, 'ORD0090', 13, 32, 'G', 'nsri.n@test.in'), 
(91, 'ORD0091', 13, 33, 'G', 'nnsri.n@test.in'), 
(92, 'ORD0092', 13, 3, 'C', 'sri.n@test.in'), 
(93, 'ORD0093', 13, 34, 'G', 'sssri.n@test.in'), 
(94, 'ORD0094', 13, 35, 'G', 'qwsri.n@test.in'), 
(95, 'ORD0095', 13, 36, 'G', 'snsri.n@test.in'), 
(96, 'ORD0096', 13, 37, 'G', 'ncnsri.n@test.in'), 
(97, 'ORD0097', 13, 38, 'G', 'nwnsri.n@test.in'), 
(98, 'ORD0098', 13, 39, 'G', 'ncnasri.n@test.in'), 
(99, 'ORD0099', 13, 40, 'G', 'ncnsasri.n@test.in'), 
(100, 'ORD0100', 13, 41, 'G', 'ncqqnasri.n@test.in'), 
(101, 'ORD0101', 13, 42, 'G', 'asdqazsri.nas123@test.in'), 
(102, 'ORD0102', 13, 43, 'G', 'nacqqnasri.n@test.in'), 
(103, 'ORD0103', 13, 3, 'C', 'sri.n@test.in'), 
(104, 'ORD0104', 13, 3, 'C', 'sri.n@test.in'), 
(105, 'ORD0105', 13, 3, 'C', 'sri.n@test.in'), 
(106, 'ORD0106', 13, 3, 'C', 'sri.n@test.in'), 
(107, 'ORD0107', 13, 3, 'C', 'sri.n@test.in'), 
(108, 'ORD0108', 13, 0, 'G', 'sri.n@test.in'), 
(109, 'ORD0109', 13, 3, 'C', 'sri.n@test.in'), 
(110, 'ORD0110', 13, 3, 'C', 'sri.n@test.in'), 
(111, 'ORD0111', 13, 44, 'G', 'qsw@test.in'), 
(112, 'ORD0112', 13, 45, 'G', 'asdasd@test.in'), 
(113, 'ORD0113', 13, 46, 'G', 'qweee@test.in'), 
(114, 'ORD0114', 13, 47, 'G', 'qweqwe@test.in'), 
(115, 'ORD0115', 13, 48, 'G', 'nsv123sri.n@test.in'), 
(116, 'ORD0116', 13, 49, 'G', 'asdasdasd@test.in'), 
(117, 'ORD0117', 13, 50, 'G', 'asdasdasdasd@test.in'), 
(118, 'ORD0118', 13, 51, 'G', 'qwerew@test.in'), 
(119, 'ORD0119', 13, 7, 'C', 'kvinocse86@test.in'), 
(120, 'ORD0120', 13, 3, 'C', 'sri.n@test.in'), 
(124, 'ORD0124', 13, 53, 'C', 'sri.n@test.in'), 
(125, 'ORD0125', 13, 0, 'G', 'sri.n@test.in'), 
(126, 'ORD0126', 13, 53, 'C', 'sri.n@test.in'), 
(127, 'ORD0127', 13, 53, 'C', 'sri.n@test.in'), 
(128, 'ORD0128', 13, 53, 'C', 'sri.n@test.in'), 
(129, 'ORD0129', 13, 53, 'C', 'sri.n@test.in'), 
(130, 'ORD0130', 13, 53, 'C', 'sri.n@test.in'), 
(131, 'ORD0131', 13, 53, 'C', 'sri.n@test.in'), 
(132, 'ORD0132', 13, 53, 'C', 'sri.n@test.in'), 
(133, 'ORD0133', 13, 53, 'C', 'sri.n@test.in'), 
(134, 'ORD0134', 13, 53, 'C', 'sri.n@test.in'), 
(135, 'ORD0135', 13, 53, 'C', 'sri.n@test.in'), 
(136, 'ORD0136', 13, 53, 'C', 'sri.n@test.in'), 
(137, 'ORD0137', 13, 53, 'C', 'sri.n@test.in'), 
(138, 'ORD0138', 13, 53, 'C', 'sri.n@test.in'), 
(139, 'ORD0139', 13, 0, 'G', 'sri.n321@test.in'), 
(140, 'ORD0140', 13, 53, 'C', 'sri.n123@test.in'), 
(141, 'ORD0141', 13, 53, 'C', 'sri.n@test.in'), 
(142, 'ORD0142', 13, 53, 'C', 'sri.n@test.in'), 
(143, 'ORD0143', 13, 55, 'G', 'vesri@test.in'), 
(144, 'ORD0144', 13, 56, 'G', 'vesri.n@test.in'), 
(145, 'ORD0145', 13, 57, 'G', 'veesri.n@test.in'), 
(146, 'ORD0146', 13, 58, 'G', 'veeisri.n@test.in'), 
(147, 'ORD0147', 13, 59, 'G', 'ren@test.in'), 
(148, 'ORD0148', 13, 60, 'G', 'ren1@test.in'), 
(149, 'ORD0149', 13, 53, 'C', 'sri.n@test.in'), 
(150, 'ORD0150', 13, 53, 'C', 'sri.n@test.in'), 
(151, 'ORD0151', 13, 53, 'C', 'sri.n@test.in'); 

CREATE TABLE IF NOT EXISTS `my_restaurant` (
    `restaurant_id` int(11) NOT NULL AUTO_INCREMENT, 
    `restaurant_name` varchar(100) NOT NULL, 
    PRIMARY KEY (`restaurant_id`) 
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=23 ; 

INSERT INTO `my_restaurant` (`restaurant_id`, `restaurant_name`) VALUES 
(1, 'Fuji Sushi'), 
(2, 'Big Pete''s Pizza'), 
(3, 'Vinos Pizza'), 
(4, 'Wafaa and Mikes Cafe'), 
(5, 'Fuji Sushi (San Marco Blvd)'), 
(6, 'Midtown Deli + Cafe'), 
(7, 'De Real Ting Cafe'), 
(8, 'Alex Delicatessen'), 
(9, 'Two Doors Down Restaurant'), 
(10, 'Ginas Deli'), 
(11, 'The Mudville Grille (Beach Blvd)'), 
(12, 'Casbah Cafe'), 
(13, 'Alexander Grill'), 
(14, 'The Southern Grill'), 
(15, 'Cool Moose Cafe'), 
(16, 'Basil: Thai and Sushi'), 
(17, 'Hot Wok'), 
(18, 'China Joy'), 
(19, 'Blu Diner'), 
(21, 'New Test restaurant'), 
(22, 'testing res'); 

我已经为顾客用restauant完成的大多数订单编写了以下SQL。

SELECT o.customeremail AS custemail, o.restaurant_id, rest.restaurant_name, COUNT(o.customeremail) AS totalordercount 
FROM my_order AS o 
INNER JOIN my_customer AS cust ON cust.customer_email = o.customeremail 
INNER JOIN my_restaurant AS rest ON rest.restaurant_id = o.restaurant_id 
WHERE o.orderid IS NOT NULL 
GROUP BY o.restaurant_id 
ORDER BY totalordercount DESC 

我得到这样的结果。

custemail   restaurant_id restaurant_name   totalordercount 
sri.n@test.in  13    Alexander Grill   79 
vinothini.k@test.in 3    Vinos Pizza    12 
sri.n@test.in  2    Big Pete's Pizza   5 
sri.n@test.in  19    Blu Diner     2 
vinothini.k@test.in 1    Fuji Sushi     1 
sri.n@test.in  8    Alex Delicatessen   1 
sri.n@test.in  5    Fuji Sushi (San Marco Blvd) 1 

SELECT * 
FROM `my_order` 
WHERE `restaurant_id` =13 
AND `customeremail` = 'sri.n@test.in' 
LIMIT 0 , 30 

我从上面查询只有71行。但我的查询显示行79

sri.n@test.in  13    Alexander Grill   79 

但我需要这样的输出。

custemail   restaurant_id restaurant_name   totalordercount 
sri.n@test.in  13    Alexander Grill   71 
vinothini.k@test.in 3    Vinos Pizza    12 
sri.n@test.in  2    Big Pete's Pizza   5 
sri.n@test.in  19    Blu Diner     2 
vinothini.k@test.in 1    Fuji Sushi     1 
sri.n@test.in  8    Alex Delicatessen   1 
sri.n@test.in  5    Fuji Sushi (San Marco Blvd) 1 

在此先感谢

Answer 1

首先，你试图通过餐厅聚集的结果集中显示客户电子邮件滥用pernicious nonstandard MySQL extension to GROUP BY。您滥用这会导致您的结果集包含custemail的任意值。

其次，这个简单的查询显示，Alexander Grill有121个订单。你声称只有71个似乎是不正确的。

SELECT COUNT(*), o.restaurant_id, r.restaurant_name 
    FROM my_order AS o 
    LEFT JOIN my_restaurant AS r ON o.restaurant_id = r.restaurant_id 
GROUP BY o.restaurant_id, r.restaurant_name 

第三，您的客户表中找不到customer_id的订单。您正在使用INNER JOIN，因此您的查询正在下降并且不计入这些订单。 LEFT JOIN将恢复丢弃的记录。但是，仍然没有使用该JOIN的结果。

第四，您的WHERE o.orderid IS NOT NULL子句是毫无意义的：该列是主键。

尝试此查询离开了my_customer表连接：

SELECT o.restaurant_id, 
     rest.restaurant_name, 
     COUNT(DISTINCT o.customer_id) AS distinctcustomercount, 
     COUNT(*) AS totalordercount 
    FROM my_order AS o 
    LEFT JOIN my_restaurant AS rest ON rest.restaurant_id = o.restaurant_id 
GROUP BY o.restaurant_id, rest.restaurant_name /* fix GROUP BY misuse */ 
ORDER BY COUNT(*) DESC, rest.restaurant_name 

我认为这不会把戏给你。它完全指定GROUP BY，它在只有一个订单的餐馆行中进行某种排序。

Answer 2

我认为您正在寻找客户电子邮件的餐馆访问计数，该电子邮件在客户表中存在。其他数字结果恰到好处，因为来自71'er的其他人只访问了一个餐厅。 如果您想要每家餐厅的顾客，则需要将顾客电子邮件添加到该群组。

SELECT o.customeremail AS custemail, 
     o.restaurant_id, rest.restaurant_name, COUNT(o.customeremail) AS totalordercount 
FROM my_order AS o 
INNER JOIN my_customer AS cust ON cust.customer_email = o.customeremail 
INNER JOIN my_restaurant AS rest ON rest.restaurant_id = o.restaurant_id 
GROUP BY o.restaurant_id, o.customeremail 
ORDER BY totalordercount DESC 

我的答案与Ollie的答案相同，除了我离开客户加入，我认为需要存在才能获得预期的结果。