对 sql 列进行排名

Question

我有这样的表：

+--------+--------+--------+
| color  | fruit  | amount |
+--------+--------+--------+
| red    | cherry |    124 |
| red    | plum   |     23 |
| green  | gauva  |    119 |
| green  | pear   |     14 |
| orange | orange |     23 |
+--------+--------+--------+

我希望它像这样添加排名。

 +------+--------+--------+--------+
 | rank | color  | fruit  | amount |
 +------+--------+--------+--------+
 |    1 | red    | cherry |    124 |
 |    2 | red    | plum   |     23 |
 |    1 | green  | gauva  |    119 |
 |    2 | green  | pear   |     14 |
 |    1 | orange | orange |     23 |
 +------+--------+--------+--------+

我需要根据每种颜色的数量（单独）对其进行排名。 这可能吗？

Answer 1

select
color, fruit, amount,
case when (if(@prev_color != color, @rank:=1, @rank:=@rank + 1)) is null then null
     when (@prev_color := color) is null then null
else @rank end as rank
from your_table
, (select @rank:=0, @prev_color := null) v
order by color, amount desc

Answer 2

如果排名是根据color 的高amount 可用性给出的，那么您还可以找到少于或多于amount 值的行数。该行数将是相关color 的rank。

select
 ( select count( color ) from fruits_table 
   where color = f.color and amount >= f.amount
 ) as 'rank',
 color, fruit, amount 
from fruits_table f
order by color, amount desc
-- order by field( color, 'red', 'green', 'orange' ), amount desc
;

您可以使用field 函数通过color 更改字段的顺序以根据需要显示在顶部或底部。请参阅上面注释的 order by 子句。

Answer 3

试试这个

SELECT  @row_num := IF(@prev_value=o.Customer,@row_num+1,1) AS RowNumber
       ,colour
       ,fruit
       ,amount
       ,@prev_value := colour
  FROM Table1,
      (SELECT @row_num := 1) x,
      (SELECT @prev_value := '') y
  ORDER BY colour,amount DESC

Answer 4

尝试使用行号函数，您可以在其中指定从哪里开始然后编号（分区依据）以及如何组织该分区内的行（排序依据）。

 | rank | color  | fruit  | amount |
 +------+--------+--------+--------+
 |    1 | red    | cherry |    124 |
 |    2 | red    | plum   |     23 |
 |    1 | green  | gauva  |    119 |
 |    2 | green  | pear   |     14 |
 |    1 | orange | orange |     23 |
 +------+--------+--------+--------+

select distinct 
  row_number() over (partition by color order by amount desc) rank,
  color,
  fruit,
  amount
from
  foo
order by
  color, amount desc

您会发现行编号从每种新颜色重新开始，并且在每种颜色中，行将按降序排列的数量排序。