Question

我有以下查询：

SELECT saturday_combinations.index, v.val AS  `row` , COUNT( * )  AS  `count` 
FROM saturday_combinations  
INNER JOIN (

SELECT ONE AS val
FROM saturday_combinations 
WHERE ONE IS NOT NULL 

UNION 
SELECT TWO AS val
FROM saturday_combinations
WHERE TWO IS NOT NULL 

UNION 
SELECT THREE AS val
FROM saturday_combinations
WHERE THREE IS NOT NULL 

UNION 
SELECT FOUR AS val
FROM saturday_combinations
WHERE FOUR IS NOT NULL 

UNION 
SELECT FIVE AS val
FROM saturday_combinations
WHERE FIVE IS NOT NULL


UNION 
SELECT SIX AS val
FROM saturday_combinations
WHERE SIX IS NOT NULL 

UNION 
SELECT SEVEN AS val
FROM saturday_combinations
WHERE SEVEN IS NOT NULL 

) v  ON v.val = saturday_combinations.ONE
  OR v.val = saturday_combinations.TWO
  OR v.val = saturday_combinations.THREE
  OR v.val = saturday_combinations.FOUR
  OR v.val = saturday_combinations.FIVE
  OR v.val = saturday_combinations.SIX
  OR v.val = saturday_combinations.SEVEN 
  GROUP BY v.val

查询的目的是提供表saturday_combinations表中ONE，TWO，THREE，FOUR，FIVE，SIX和SEVEN列中包含的不同值的计数。但是我想设置一个desc限制4，以便它只根据最后4行（最后4个最大索引）执行计数。但我没有让它与工会合作。最后添加顺序和限制仅限于最终选择，而不是获取最后4行并计算它们的分布。有什么提示吗？

表模式如下：

index | ONE|TWO|THREE|FOUR|FIVE|SIX|SEVEN
 1       1   3   7     10    11  12  13
 2       3   4   5     30    31  22  23
 3       1   2   3      4     5   6   7
 4       1   2   3      4     5   6   7
 5       1   2   3      4     5   6   7
 6       1   2   3      4     5   6   7
 7       1   2   3      4     5   6   7
 8       1   2   3      4     5   6   7
 9       1   2   3      4     5   6   7
 10      1   2   3      4     5   6   7

索引是自动递增的，ONE-SEVEN具有整数值。

表格中有大约3000行，我想根据最后n行计算每个值的出现次数。

Ideal result for the last n rows where n = last 3 rows should be
Numbers|Count
   1       3
   2       3
   3       3
   4       3
   5       3
   6       3
   7       3

如果我增加n以包含最后6行，则其计数应该增加。如果我可以持续10行，则计数应该增加，其他数字应该随计数出现。

这是真实表格样本的链接。 http://sqlfiddle.com/#!2/d035b

Answer 1

如果我的评论回答为yes，那么您可以尝试以下方法。当您需要将limit, order by添加到union selects时，您需要使用括号union queries包裹()。

的 SQLFIDDLE DEMO

代码：

(SELECT ONE AS val FROM saturday_combinations WHERE ONE IS NOT NULL order by ONE desc limit 4) UNION (SELECT TWO AS val FROM saturday_combinations WHERE TWO IS NOT NULL order by TWO desc limit 4) UNION (SELECT THREE AS val FROM saturday_combinations WHERE THREE IS NOT NULL order by THREE desc limit 4)

如果我的评论回答为no，请澄清。

以下是基于您的样本日期的代码：

select distinct x.one as uniqunumbers, count(x.one) as counts from( sELECT DISTINCT 'one' AS col1, one FROM sat_comb UNION ALL SELECT DISTINCT 'two' AS col1, two FROM sat_comb UNION ALL SELECT DISTINCT 'three' AS col1, three FROM sat_comb ) as x group by x.one; UNIQUNUMBERS COUNTS 1 1 3 2 4 1 5 1 7 1

根据OP编辑澄清并更新了问题。

引用：“但是我想限制它，以便它首先占用最后n行，然后计算这n行中的值。这意味着，如果我有3列，3000行和35行随机出现在这3000行中的整数应该计算每个整数出现的次数。“

SQLFIDDLE DEMO2

查询：

select x.one as uniqunumbers, count(x.one) as counts from( (sELECT DISTINCT 'one' AS col1, one FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'two' AS col1, two FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'three' AS col1, three FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'four' AS col1, four FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'five' AS col1, five FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'six' AS col1, six FROM sat_comb order by id desc limit 4) UNION ALL (SELECT DISTINCT 'seven' AS col1, seven FROM sat_comb order by id desc limit 4) ) as x group by x.one;

输出：

UNIQUNUMBERS COUNTS 2 4 3 3 4 3 5 4 6 4 8 3 9 4 20 3

Answer 2

也许我在您的请求中遗漏了某些内容，但根据您所需的结果，为什么不只是取消数据并执行计数。

select value, count(*) Total
from
(
  select 'one' col, one value
  from saturday_combinations
  union all
  select 'two' col, two value
  from saturday_combinations
  union all
  select 'three' col, three value
  from saturday_combinations
  union all
  select 'four' col, four value
  from saturday_combinations
  union all
  select 'five' col, five value
  from saturday_combinations
  union all
  select 'six' col, six value
  from saturday_combinations
  union all
  select 'seven' col, seven value
  from saturday_combinations
) src
group by value

请参阅SQL Fiddle with Demo

您的样本结果是：

| VALUE | TOTAL |
-----------------
|     1 |     1 |
|     3 |     2 |
|     4 |     1 |
|     5 |     1 |
|     7 |     1 |
|    10 |     1 |
|    11 |     1 |
|    12 |     1 |
|    13 |     1 |
|    22 |     1 |
|    23 |     1 |
|    30 |     1 |
|    31 |     1 |

编辑＃1：根据您的更新，这可能需要您：

select value, count(*)
from
(
  select col, value
  from
  (
    select 'one' col, one value
    from saturday_combinations
    order by one 
    limit 3
  ) one
  union all
  select col, value
  from
  (
    select 'two' col, two value
    from saturday_combinations
    order by two desc
    limit 3
  ) two
  union all
  select col, value
  from
  (
    select 'three' col, three value
    from saturday_combinations
    order by three 
    limit 3
  ) three
  union all
  select col, value
  from
  (
    select 'four' col, four value
    from saturday_combinations
    order by four 
    limit 3
  ) four
  union all
  select col, value
  from
  (
    select 'five' col, five value
    from saturday_combinations
    order by five 
    limit 3
  ) five
  union all
  select col, value
  from
  (
    select 'six' col, six value
    from saturday_combinations
    order by six 
    limit 3
  ) six
  union all
  select col, value
  from
  (
    select 'seven' col, seven value
    from saturday_combinations
    order by seven 
    limit 3
  ) seven
) src
group by value

请参阅SQL Fiddle with Demo

结果：

| VALUE | COUNT(*) |
--------------------
|     1 |        3 |
|     2 |        1 |
|     3 |        4 |
|     4 |        4 |
|     5 |        3 |
|     6 |        3 |
|     7 |        3 |

Answer 3

如果您想查看最终解决方案： http://sqlfiddle.com/#!2/867a6/13 感谢@bonCodigo的所有帮助

内部联接和子查询的mysql限制

3 个答案:

根据OP编辑澄清并更新了问题。