MySQL在显示所有联系人组时显示有限数量的联系人

我有一本称为联系人的通讯录。为了帮助组织联系人，我有一些小组（例如家庭、朋友、工作）。我想为每组显示4或10个联系人示例。这适用于列出所有组的组索引页面，但不适用于每个组的联系人完整列表（仅适用于专用组页面）

分组表和列

电子邮件组

id

，

id\u用户

，

name

联系人表和列

email\u联系人

id

，

id\u组

，

id\u用户

，

名称

我一直在做这件事，但是得到了一个错误的

c1

列名

SELECT 
eg.id, 
eg.name, 
(SELECT c1.name FROM email_contacts AS c1 WHERE id_user='1' LIMIT 0,1) AS contact_1, 
(SELECT c2.name FROM email_contacts AS c1 WHERE id_user='1' LIMIT 1,1) AS contact_2, 
(SELECT c3.name FROM email_contacts AS c3 WHERE id_user='1' LIMIT 2,1) AS contact_3, 
(SELECT c4.name FROM email_contacts AS c4 WHERE id_user='1' LIMIT 3,1) AS contact_4 
FROM email_groups AS eg 
INNER JOIN email_contacts AS ec on ec.id=eg.id_group

---

您在子查询中提供了两次别名

C1

，我想第二个子查询应该是

C2

，您正在尝试选择

C2.name

，但您提供的别名是

C1

从电子邮件联系人中选择C2.name作为C1

SELECT 
eg.id, 
eg.name, 
(SELECT c1.name FROM email_contacts AS c1 WHERE id_user='1' LIMIT 0,1) AS contact_1, 
(SELECT c2.name FROM email_contacts AS c2 WHERE id_user='1' LIMIT 1,1) AS contact_2, 
(SELECT c3.name FROM email_contacts AS c3 WHERE id_user='1' LIMIT 2,1) AS contact_3, 
(SELECT c4.name FROM email_contacts AS c4 WHERE id_user='1' LIMIT 3,1) AS contact_4 
FROM email_groups AS eg 
INNER JOIN email_contacts AS ec on ec.id=eg.id_group

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啊，我确实让它正常工作了，但是我错过了那个错误，谢谢。