Question

表

id  Company  Name   Price
1   xxx      namea    1
2   xxx      nameh    1.1
3   xxx      nameg    2
4   yyy      namef    1.5
5   zzz      named    1.7
6   zzz      names    0.9

我需要这样的结果

dCounter   Company  Name   Price
1           xxx     namea    1
1           xxx     nameh    1.1
1           xxx     nameg    2
2           yyy     namef    1.5
3           zzz     named    1.7
3           zzz     names    0.9

正如您所看到的，我们计算公司的数量，它应该适用于分页。这意味着如果我们在每秒页面上有x2条目，那么将会有dCounter 1和2，在第三页上只有3个。

问题出在dCounter中，因为它应该再次计入每个页面。由公司ASC订购，名称为ASC，价格为ASC＆＃34;。

我该如何为此创建查询？

Answer 1

按公司计算排名（）。

select
    @rn := case when @company <> company then @rn + 1 else @rn end as rn,
    @company := company as cia,
    Name,
    Price
from
    (select @rn := 0) i,
    (select @company := company as company, Name, Price
     from ff order by company) t;

结果：

+----+-----+-------+-------+
| rn | cia | Name  | Price |
+----+-----+-------+-------+
| 1  | xxx | namea | 1,00  |
+----+-----+-------+-------+
| 1  | xxx | nameh | 1,10  |
+----+-----+-------+-------+
| 1  | xxx | nameg | 2,00  |
+----+-----+-------+-------+
| 2  | yyy | namef | 1,50  |
+----+-----+-------+-------+
| 3  | zzz | named | 1,70  |
+----+-----+-------+-------+
| 3  | zzz | names | 0,90  |
+----+-----+-------+-------+

可在此处查看：http://rextester.com/ACY4401

Mysql，独特的计数器

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