MySQL group_concat 与连接

Posted 2023-02-24

【中文标题】MySQL group_concat 与连接

【英文标题】：MySQL group_concat with join

【发布时间】：2015-02-25 13:37:28

【问题描述】：

我有一张联系表。每个联系人可以有多个电话号码，具有不同或相同的表。同样，每个联系人可以拥有多封具有不同或相同标签的电子邮件。我需要选择属于特定联系人的所有不同电话号码和电子邮件 ID。

CREATE TABLE IF NOT EXISTS `contact` (
  `id` int(8) unsigned NOT NULL ,
  `fname` varchar(64)  NOT NULL,
  `lname` varchar(64)  NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=latin1  ;
CREATE TABLE IF NOT EXISTS `phone` (
  `id` int(8) unsigned NOT NULL ,
  `sourceid` int(8) unsigned NOT NULL ,
   `type` varchar(16)  NOT NULL,
  `phone` varchar(16)  NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=latin1  ;
CREATE TABLE IF NOT EXISTS `email` (
  `id` int(8) unsigned NOT NULL ,
  `sourceid` int(8) unsigned NOT NULL ,
  `type` varchar(16)  NOT NULL,
  `email` varchar(128)  NOT NULL
) ENGINE=InnoDB  DEFAULT CHARSET=latin1  ;

INSERT INTO contact values ( 1,'john'      ,'j' ),
(2, 'jose'      ,'f' ),
(3, 'test'      ,'k' ),
(4, 'tester'      ,'j' );


INSERT INTO phone values( 1 ,1, 'Home', '123456' ),
( 2 ,1, 'Home', '123456342' ),
( 3 ,1, 'Office', '12345645' ),
( 4 ,1, 'Mobile', '1234567' ),
( 5 ,2, 'Home', '123456' ),
( 5 ,2, 'Home', '987556' );

INSERT INTO email values
( 1 ,1, 'Home', '[e-mail]' ),
( 2 ,1, 'Home', '[e-mail]' ),
( 3 ,1, 'Office', '[e-mail]' ),
( 4 ,2, 'Home', '[e-mail]' ),
( 5 ,4, 'Home', '[e-mail]' );

我尝试了 GROUP_CONCAT，但它的标签条目重复。

SELECT C.id, fname, lname
, GROUP_CONCAT(ph.sourceid), 
GROUP_CONCAT(em.sourceid), 
GROUP_CONCAT(ph.type), GROUP_CONCAT(ph.phone),
GROUP_CONCAT(em.type), GROUP_CONCAT(em.email)
FROM contact AS C 
LEFT  JOIN phone AS PH ON PH.sourceid = C.id 
LEFT  JOIN email EM ON EM.sourceid = C.id 
WHERE C.id='1'
GROUP BY C.id

SQL FIDDLE

【参考方案1】：

试试这个：

SELECT c.id, c.fname, c.lname, 
       ph.PhoneType, ph.PhoneNos, 
       em.EmailType, em.EmailIds
FROM contact AS c 
LEFT JOIN (SELECT ph.sourceid, GROUP_CONCAT(ph.type) AS PhoneType, GROUP_CONCAT(ph.phone) AS PhoneNos 
           FROM phone AS ph 
           GROUP BY ph.sourceid
          ) AS ph ON ph.sourceid = c.id 
LEFT JOIN (SELECT em.sourceid, GROUP_CONCAT(em.type) AS EmailType, GROUP_CONCAT(em.email) AS EmailIds
           FROM email AS em 
           GROUP BY em.sourceid
          ) AS em ON em.sourceid = c.id 
WHERE c.id = '1'
GROUP BY c.id

查看SQL FIDDLE DEMO

输出

| ID | FNAME | LNAME |               PHONETYPE |                          PHONENOS |        EMAILTYPE |                                   EMAILIDS |
|----|-------|-------|-------------------------|-----------------------------------|------------------|--------------------------------------------|
|  1 |  john |     j | Home,Home,Office,Mobile | 123456,123456342,12345645,1234567 | Home,Home,Office | [e-mail],[e-mail],[e-mail] |

【讨论】：

对不起，我忘了说我也需要标签（类型）。如果我添加 DISTINCT，则不会选择不同的标签。

SELECT C.id, fname, lname, GROUP_CONCAT(DISTINCT ph.phone), GROUP_CONCAT(DISTINCT em.email) ,GROUP_CONCAT(DISTINCT em.type) FROM contact AS C LEFT JOIN phone AS PH ON PH.sourceid = C.id LEFT JOIN email AS EM ON EM.sourceid = C.id WHERE C.id = '1' GROUP BY C.id 这将返回电子邮件类型 Home 和 Office，但有两个 Home 类型的电子邮件在表中