我有一个通讯录，称为通讯录。为了帮助组织联系人，我有一些小组（例如，家人，朋友，工作）。我想说每组要显示的4到10个联系人示例。这适用于列出所有组的组索引页面，但并不旨在每个组都有完整的联系人列表（仅适用于专用组页面）。
组表和列
email_groups
id，id_user，name
联系人表和列
email_contacts
id，id_group，id_user，name
我一直在努力，但是得到的列名称错误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 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
您已经C1在子查询中提供了两次别名，我想这将是C2第二个子查询，您正在尝试选择，c2.name但您已提供了别名c1 SELECT c2.name FROM email_contacts AS 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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