Question

我这里有产品表

product_id, popularity, date_add

我想选择产品并按人气排序，并在每5行（5,10,15，...）中添加新产品。能够再次选择第2页。输出应该是这样的。

popularity #1 
popularity #2 
popularity #3 
popularity #4
latest #1
popularity #5
popularity #6
popularity #7
popularity #8
latest #2
popularity #9
popularity #10
popularity #11
popularity #12
latest #3

我该怎么做？谢谢！

Answer 1

DDL：

create table Te (product_id int, popularity int, date_add int);

insert into Te (product_id, popularity, date_add)
values
(1,      10,               1),
(2,      21,               1),
(3,      12,               1),
(4,      23,               1),
(5,      5,                1),
(6,      2,                5),
(7,      3,                6),
(8,       1,                7),
(9,       1,                1),
(11,      210,            11),
(12,      221,            11),
(13,      212,            11),
(14,      223,            11),
(15,      25,             11),
(16,      22,             15),
(17,      23,             16),
(18 ,      21,             27),
(19,       21,             31);

SQL（使用循环和诸如此类的东西很容易构建）

(select * from Te order by popularity desc LIMIT 5 OFFSET 0) 
UNION ALL
(select * from Te order by date_add desc LIMIT 1 OFFSET 0) 
UNION ALL

(select * from Te order by popularity desc LIMIT 5 OFFSET 5) 
UNION ALL
(select * from Te order by date_add desc LIMIT 1 OFFSET 1) 
UNION ALL

(select * from Te order by popularity desc LIMIT 5 OFFSET 10) 
UNION ALL
(select * from Te order by date_add desc LIMIT 1 OFFSET 2) 
UNION ALL

(select * from Te order by popularity desc LIMIT 5 OFFSET 15) 
UNION ALL
(select * from Te order by date_add desc LIMIT 1 OFFSET 3)

结果：

product_id  popularity  date_add

    14        223        11
    12        221        11
    13        212        11
    11        210        11
    15        25         11
    *19       21         31
    17        23         16
    4         23         1
    *16       22         15
    *19       21         31
    *2        21         1
    18        21         27
    *2        21         1
    3         12         1
    1         10         1
    5         5          1
    7         3          6
    17        23         16
    6         2          5
    9         1          1
    8         1          7
    *16       22         15

你可以通过id看到重复项，你可能想过滤那些......

Answer 2

回答我自己的问题。

不，我仍然无法通过纯SQL来实现。

到目前为止，我可以通过添加名为＆＃34; sort＆＃34;的额外列来实现此目的。通过这个额外的列，我可以将任何我想要的东西撒到列表中。查询简单快捷。

唯一的缺点是更新排序值的额外工作。但是crontab可以在每个小时左右轻松完成。

如何在每第n行选择混合结果？

2 个答案: