SQL对每行中的列进行排序,并基于此对行进行排序
我可以使用什么SQL select查询对每行进行排序,然后对已排序的行进行排序 例如:表格选项卡(c1、c2、c3、c4) 查询必须给出:SQL对每行中的列进行排序,并基于此对行进行排序,sql,sqlite,sorting,select,Sql,Sqlite,Sorting,Select,我可以使用什么SQL select查询对每行进行排序,然后对已排序的行进行排序 例如:表格选项卡(c1、c2、c3、c4) 查询必须给出: 1,2,6,7 2,3,5,9 2,4,5,8 这只是一个开始,也许不是最“干净”的代码,但它会起作用 SELECT CASE WHEN C1 < C2 THEN CASE WHEN C1 < C3 THEN C1 ELSE C3 END ELSE CAS
1,2,6,7
2,3,5,9
2,4,5,8
这只是一个开始,也许不是最“干净”的代码,但它会起作用
SELECT CASE WHEN C1 < C2 THEN
CASE WHEN C1 < C3 THEN C1 ELSE C3 END
ELSE
CASE WHEN C2 < C3 THEN C2 ELSE C3 END
END
From YourTable
选择C1
这将首先选择最小的元素。
再来三杯,你就可以走了。。
一旦你有了这个结果集,你就可以按第一列排序了。这只是一个开始,也许不是最“干净”的代码,但它可以工作
SELECT CASE WHEN C1 < C2 THEN
CASE WHEN C1 < C3 THEN C1 ELSE C3 END
ELSE
CASE WHEN C2 < C3 THEN C2 ELSE C3 END
END
From YourTable
SELECT
MIN(c1, c2, c3, c4) AS new_c1,
CASE MIN(c1, c2, c3, c4) WHEN c1 THEN MIN(c2, c3, c4)
WHEN c2 THEN MIN(c1, c3, c4)
WHEN c3 THEN MIN(c1, c2, c4)
WHEN c4 THEN MIN(c1, c2, c3)
END AS new_c2,
CASE MAX(c1, c2, c3, c4) WHEN c1 THEN MAX(c2, c3, c4)
WHEN c2 THEN MAX(c1, c3, c4)
WHEN c3 THEN MAX(c1, c2, c4)
WHEN c4 THEN MAX(c1, c2, c3)
END AS new_c3,
MAX(c1, c2, c3, c4) AS new_c4
FROM tab
ORDER BY new_c1, new_c2, new_c3, new_c4
选择C1
这将首先选择最小的元素。
再来三杯,你就可以走了。。
获得此结果集后,可以按第一列排序
SELECT
MIN(c1, c2, c3, c4) AS new_c1,
CASE MIN(c1, c2, c3, c4) WHEN c1 THEN MIN(c2, c3, c4)
WHEN c2 THEN MIN(c1, c3, c4)
WHEN c3 THEN MIN(c1, c2, c4)
WHEN c4 THEN MIN(c1, c2, c3)
END AS new_c2,
CASE MAX(c1, c2, c3, c4) WHEN c1 THEN MAX(c2, c3, c4)
WHEN c2 THEN MAX(c1, c3, c4)
WHEN c3 THEN MAX(c1, c2, c4)
WHEN c4 THEN MAX(c1, c2, c3)
END AS new_c3,
MAX(c1, c2, c3, c4) AS new_c4
FROM tab
ORDER BY new_c1, new_c2, new_c3, new_c4
- 看到它在一个小房间里工作吗
- 有关
和min()
函数,请参阅max()
- 看到它在一个小房间里工作吗
- 有关
和min()
函数,请参阅max()
CREATE TEMPORARY TABLE nums2
(
Row int,
V int
);
INSERT INTO nums2
SELECT *
FROM
(
SELECT rowid Row, c1 V FROM nums
UNION ALL
SELECT rowid Row, c2 V FROM nums
UNION ALL
SELECT rowid Row, c3 V FROM nums
UNION ALL
SELECT rowid Row, c4 V FROM nums
)
ORDER BY Row, V;
SELECT n1.V v1, n2.V v2, n3.V v3, n4.V v4
FROM nums2 n1
INNER JOIN nums2 n2 ON n1.Row = n2.Row AND n2.rowid = n1.rowid + 1
INNER JOIN nums2 n3 ON n1.Row = n3.Row AND n3.rowid = n1.rowid + 2
INNER JOIN nums2 n4 ON n1.Row = n4.Row AND n4.rowid = n1.rowid + 3
WHERE ((n1.rowid - 1) % 4 = 0)
ORDER BY n1.V, n2.V, n3.V, n4.V
它使用一个临时表(nums2
)保存“线性化”行,然后使用隐藏列rowid
将行分组
测试人员:
最后一个选择可以稍微简化:
SELECT n1.V v1, n2.V v2, n3.V v3, n4.V v4
FROM nums2 n1
INNER JOIN nums2 n2 ON n2.rowid = n1.rowid + 1
INNER JOIN nums2 n3 ON n3.rowid = n1.rowid + 2
INNER JOIN nums2 n4 ON n4.rowid = n1.rowid + 3
WHERE ((n1.rowid - 1) % 4 = 0)
ORDER BY n1.V, n2.V, n3.V, n4.V
因为WHERE
表达式将“选择”每行的最低值
测试人员:
查询很容易扩展 可能的解决方案:
CREATE TEMPORARY TABLE nums2
(
Row int,
V int
);
INSERT INTO nums2
SELECT *
FROM
(
SELECT rowid Row, c1 V FROM nums
UNION ALL
SELECT rowid Row, c2 V FROM nums
UNION ALL
SELECT rowid Row, c3 V FROM nums
UNION ALL
SELECT rowid Row, c4 V FROM nums
)
ORDER BY Row, V;
SELECT n1.V v1, n2.V v2, n3.V v3, n4.V v4
FROM nums2 n1
INNER JOIN nums2 n2 ON n1.Row = n2.Row AND n2.rowid = n1.rowid + 1
INNER JOIN nums2 n3 ON n1.Row = n3.Row AND n3.rowid = n1.rowid + 2
INNER JOIN nums2 n4 ON n1.Row = n4.Row AND n4.rowid = n1.rowid + 3
WHERE ((n1.rowid - 1) % 4 = 0)
ORDER BY n1.V, n2.V, n3.V, n4.V
它使用一个临时表(nums2
)保存“线性化”行,然后使用隐藏列rowid
将行分组
测试人员:
最后一个选择可以稍微简化:
SELECT n1.V v1, n2.V v2, n3.V v3, n4.V v4
FROM nums2 n1
INNER JOIN nums2 n2 ON n2.rowid = n1.rowid + 1
INNER JOIN nums2 n3 ON n3.rowid = n1.rowid + 2
INNER JOIN nums2 n4 ON n4.rowid = n1.rowid + 3
WHERE ((n1.rowid - 1) % 4 = 0)
ORDER BY n1.V, n2.V, n3.V, n4.V
因为WHERE
表达式将“选择”每行的最低值
测试人员:
查询很容易扩展 您可以将表格转换为
(行、列、值)
格式。然后,您可以对其进行排序,并将其解压回(行号,val1,val2,val3,val4)
格式
; with with_numbers as
(
select row_number() over (order by c1) rn
, *
from tab
)
, normalized(rn, nr) as
(
select rn, c1 from with_numbers
union all
select rn, c2 from with_numbers
union all
select rn, c3 from with_numbers
union all
select rn, c4 from with_numbers
)
, normalized_with_number as
(
select row_number() over (partition by rn order by nr) rn2
, *
from normalized
)
, sorted as
(
select max(case when rn2 = 1 then nr end) c1
, max(case when rn2 = 2 then nr end) c2
, max(case when rn2 = 3 then nr end) c3
, max(case when rn2 = 4 then nr end) c4
from normalized_with_number
group by
rn
)
select *
from sorted
order by
c1
, c2
, c3
, c4
您可以将表格转换为
(行、列、值)
格式。然后,您可以对其进行排序,并将其解压回(行号,val1,val2,val3,val4)
格式
; with with_numbers as
(
select row_number() over (order by c1) rn
, *
from tab
)
, normalized(rn, nr) as
(
select rn, c1 from with_numbers
union all
select rn, c2 from with_numbers
union all
select rn, c3 from with_numbers
union all
select rn, c4 from with_numbers
)
, normalized_with_number as
(
select row_number() over (partition by rn order by nr) rn2
, *
from normalized
)
, sorted as
(
select max(case when rn2 = 1 then nr end) c1
, max(case when rn2 = 2 then nr end) c2
, max(case when rn2 = 3 then nr end) c3
, max(case when rn2 = 4 then nr end) c4
from normalized_with_number
group by
rn
)
select *
from sorted
order by
c1
, c2
, c3
, c4
在应用程序层,而不是数据库中进行操作。@Yosi:ORDER BY易于使用,但我不知道如何对每个应用程序中的列进行排序row@slashmais如果列的数量是固定的(并且很小),那么一个非常复杂的
案例可以解决这个问题。只有24种可能的四列排序(4!):-):-)也许您可以使用交叉应用创建一些复杂的查询,但我认为这几乎是不可能的。可能您需要调用外部编程来完成这项工作。@fancyPants:我正在使用sqlite数据库浏览器&希望它可以通过查询完成,而不必编写应用程序。请在应用程序层而不是数据库中完成。@Yosi:Easy-useORDER BY
,但我不知道如何对每一行中的列进行排序row@slashmais如果列的数量是固定的(并且很小),那么一个非常复杂的案例可以解决这个问题。只有24种可能的四列排序(4!):-):-)也许您可以使用交叉应用创建一些复杂的查询,但我认为这几乎是不可能的。可能您需要调用外部编程来完成这项工作。@fancyPants:我使用的是sqlite数据库浏览器&希望它可以通过查询完成,而不必编写应用程序。这会使比较变得有点烦人,但概念是一样的。会使比较变得有点烦人,但这是同一个概念。他要求使用SQLite,所以没有CTE和行号
:-):-)@xanatos:haha。。。德拉特。我觉得我很聪明:DHe要求使用SQLite,所以没有CTE和行号
:-):-)@xanatos:haha。。。德拉特。我觉得我很聪明:D