[英]Pagination in one to many relationship with PHP and MySQL
我想显示数据库表中的6条记录。 2个表之间存在一对多关系。 使用自定义映射器,我将这些记录映射如下。
$result = [
0=>[
"name"=>"jithin",
"phone"=>"907856",
"messages"=>[
0=>[
"title"=>"text messgae"
],
1=>[
"title"=>"Data messgae"
]
]
],
1=>[
"name"=>"Rijin",
"phone"=>"90247856",
"messages"=>[
0=>[
"title"=>"text messgae"
],
1=>[
"title"=>"Data messgae"
]
]
]
]
QUERY
"SELECT u.* , m.* FROM user u INNER JOIN messages m ON m.userId = u.id
WHERE m.date BETWEEN "12-12-2015" AND "12-12-2018" LIMIT 0, 6;
该查询将返回如下数据
userId | name | messages|
-------|------|---------|
1 |jithin| hai |
1 |jithin| hello |
1 |jithin| Why? |
2 |Rijin | hai |
2 |Rijin | Where |
2 |Rijin | Why? |
-------------------------
但是我需要另外4个人的另外4条记录。 我正在使用php和mysql5.7。
如果我了解您的需求:
SELECT u.id, u.userName , m.message
FROM user u
INNER JOIN messages m ON m.userId = u.id
INNER JOIN (SELECT u.id as user_id FROM user u LIMIT 0, 6) as users
ON users.user_id = u.id
WHERE m.date BETWEEN '12-12-2015' AND '12-12-2018';
最后,我找到了这个问题的答案。
"SELECT u.* , m.* FROM user u
INNER JOIN messages m ON m.userId = u.id
INNER JOIN (SELECT DISTINCT u.id as user_id FROM user u
INNER JOIN messages m ON m.userId = u.id
WHERE m.date BETWEEN "12-12-2015"
AND "12-12-2018" LIMIT 0, 6)
AS distinct_users ON distinct_users.user_id=u.id
WHERE m.date BETWEEN "12-12-2015" AND "12-12-2018";
这将返回准确的6个人消息,我们可以轻松管理分页。 如果您还有另一个简单的选择。 请在这里发布。
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