[英]Php, MySql join tables, limit records per category
I have two tables: 我有两个表:
Items 物品
ID Name Model_ID
---------------------------------
1 2010 Audi L1 1
2 2014 BMW X2 2
3 2015 Acura L3 3
4 2016 BMW X5 2
5 2012 BMW X3 2
6 2013 BMW X4 2
7 2015 Acura L1 3
8 2011 Acura L2 3
9 2011 Audi L5 1
10 2012 Audi L6 1
Brands 品牌品牌
Model_ID Title
---------------------
1 Audi
2 BMW
3 Acura
And following query: 和以下查询:
SELECT
b.name,
i.title,
FROM
items AS i
INNER JOIN brands AS b
ON b.Model_ID = i.Model_ID
WHERE i.status = 1
ORDER BY i.created DESC;
The above produces working array: 上面产生了工作数组:
Array
(
[0] => stdClass Object
(
[name] => 2010 Audi L1
[title] => Audi
)
[1] => stdClass Object
(
[name] => 2014 MBW X5
[title] => BMW
)
...
)
Than I use custom function to loop through array and end up with 比我使用自定义函数遍历数组并最终得到
Array
(
[Acura] => Array
(
[0] => stdClass Object
(
[name] => 2015 Acura L1
[title] => Acura
)
...
)
[BWM] => Array
(
[0] => stdClass Object
(
[name] => 2016 BMW X5
[title] => BWM
)
...
)
[Audi] => Array
(
[0] => stdClass Object
(
[name] => 2010 Audi L1
[title] => Audi
)
...
)
)
Now I can use foreach loop and limit each Brand to show x number of items, but the idea is to do it within database, so instead of pulling all records, I would like to be able to limit to 5 items per each brand. 现在,我可以使用foreach循环并限制每个品牌显示x个项目,但是这个想法是在数据库中完成,因此,除了提取所有记录,我希望每个品牌可以限制5个项目。
Note: I did not list the rest of the table fields, such as created, which is used to sort records. 注意:我未列出用于对记录进行排序的其余表字段,例如创建的。
$q = 'SELECT Model_ID AS id FROM brands ORDER BY title ASC';
$ q ='从品牌ORDER BY标题ASC中选择Model_ID AS ID';
$r = mysql_query($q);$ r = mysql_query($ q);
$model_ids = array();$ model_ids = array();
while($brand = mysql_fetch_assoc($r)) { $model_ids[] = $brand['id'];while($ brand = mysql_fetch_assoc($ r)){$ model_ids [] = $ brand ['id']; }
}
$q = array(); foreach($mode_ids AS $model_id) { $q[] = '(SELECT b.name, i.title FROM items AS i INNER JOIN brands AS b ON b.Model_ID = i.Model_ID WHERE b.Model_ID = '.(int)$model_id.' AND i.status = 1 ORDER BY i.created DESC LIMIT 5)'; } if(!empty($q)) { $q = implode(' UNION ALL ', $q); $r = mysql_query($q); while($record = mysql_fetch_object($r)) { var_dump($record); } }
as result we'll get records of resulting query: 结果,我们将获得结果查询的记录:
(SELECT b.name, i.title FROM items AS i INNER JOIN brands AS b ON b.Model_ID = i.Model_ID WHERE b.Model_ID=1 AND i.status = 1 ORDER BY i.created DESC LIMIT 5)
(从项目中选择“ b.name”,“ i.title”作为“ i i.INNER JOIN”品牌作为“ b ON”。b.Model_ID= i.Model_ID,b.Model_ID = 1并且i.status = 1由i。创建的DESC LIMIT 5)
UNION ALL
全联盟
(SELECT b.name, i.title FROM items AS i INNER JOIN brands AS b ON b.Model_ID = i.Model_ID WHERE b.Model_ID=2 AND i.status = 1 ORDER BY i.created DESC LIMIT 5)
(从项目中选择b.name,i.title作为AS i INNER JOIN品牌作为b.b.Model_ID = i.Model_ID WHERE b.Model_ID = 2 AND i.status = 1按i。创建的DESC LIMIT 5排序)
UNION ALL
全联盟
(SELECT b.name, i.title FROM items AS i INNER JOIN brands AS b ON b.Model_ID = i.Model_ID WHERE b.Model_ID=3 AND i.status = 1 ORDER BY i.created DESC LIMIT 5)
(从项目中选择“ b.name”,“ i.title”作为“ i i.INNER JOIN”品牌作为“ b ON”。b.Model_ID= i.Model_ID WHERE b.Model_ID = 3并且i.status = 1由i。创建的DESC LIMIT 5)
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