[英]PHP - SQL: fetching results in round robin fashion
I have a table, which consists of 3 fields: 我有一个表,其中包含3个字段:
Every time I get the results, it should give me 5 names whose status = 1. Suppose the db contains following: 每次获得结果时,它应该给我5个状态= 1的名称。假设数据库包含以下内容:
id name status
1 A 1
2 B 1
3 C 0
4 D 1
5 E 0
6 F 0
7 H 1
8 I 1
9 J 1
10 K 1
11 L 1
12 M 0
1st time, fetch should return: A,B,D,H,I (5 records) 第一次,访存应返回:A,B,D,H,I(5条记录)
2nd time, fetch should return: J,K,L,A,B (5 records) 第二次,访存应返回:J,K,L,A,B(5条记录)
UPDATE : I don't want typical pagenation. 更新 :我不希望典型的分页。 Consider I have 12 available names from A1 to A12.
考虑一下我有12个可用的名字,从A1到A12。 The first fetch should return A1-A5, second fetch A6-A10 and third fetch A11, A12, A1, A2, A3.
第一次读取应返回A1-A5,第二次读取A6-A10,第三次返回A11,A12,A1,A2,A3。 So when I reach the end, I need to get records starting from the first to fill the 5 slots.
因此,当我到达结尾时,我需要从第一个开始获取记录以填充5个插槽。
i am doing it in php with mysql 我正在用mysql在php中进行操作
This looks like some sort of job allocation script? 这看起来像某种工作分配脚本吗?
You need 2 things: 您需要两件事:
Then you can write your query as 然后,您可以将查询写为
SELECT
id, name
FROM
table
WHERE
status=1
ORDER BY
(bignum + id) MOD (bigNum + lastID + 1)
LIMIT 5
Shazaam! !
Keep track of the ids of the records returned, and for the following queries do: 跟踪返回的记录的ID,对于以下查询,请执行以下操作:
select top 5 *
from (
select top 5 *
from MyTable
where status = 1
and id not in (1,2,4,7,8)
order by name
union
select top 5 *
from MyTable
where status = 1
order by name
) a
$q = mysql_query("SELECT name FROM table WHERE status = 1 LIMIT 5);
while ($row = mysql_fetch_row($q))
{
.... //first 5
}
$q = mysql_query("SELECT name FROM table WHERE status = 1 LIMIT 5,5);
while ($row = mysql_fetch_row($q))
{
.... //second 5
}
this uses the offset functionality of mysql- think of it as pagination for your results. 它使用mysql的offset功能-将其视为您的结果的分页。
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