如何根据 SQL Server 中的数据长度对列进行排序

Question

众所周知，一般排序是使用 order by。我想要执行的类型是不同的。我想要表格中间的最小长度值 n 顶部和底部的最大长度值。一半应该下降，另一半应该上升。你们能帮忙吗。这是一道面试题。

Answer 1

这是一种方式：

;WITH CTE AS
(
    SELECT  *, 
            RN = ROW_NUMBER() OVER(ORDER BY LEN(YourColumn))
    FROM dbo.YourTable
)
SELECT *
FROM CTE
ORDER BY RN%2, (CASE WHEN RN%2 = 0 THEN 1 ELSE -1 END)*RN DESC

Answer 2

测试数据

DECLARE @Table TABLE
(ID INT, Value VARCHAR(10))

INSERT INTO @Table VALUES 
(1 , 'A'),
(2 , 'AB'),
(3 , 'ABC'),
(4 , 'ABCD'),
(5 , 'ABCDE'),
(6 , 'ABCDEF'),
(7 , 'ABCDEFG'),
(8 , 'ABCDEFGI'),
(9 , 'ABCDEFGIJ'),
(10 ,'ABCDEFGIJK')

查询

;WITH CTE AS (
SELECT * 
      ,NTILE(2) OVER (ORDER BY LEN(Value) DESC) rn
FROM @Table )
SELECT *
FROM CTE 
ORDER BY CASE WHEN rn = 1 THEN LEN(Value) END DESC
         ,CASE WHEN rn = 2 THEN LEN(Value) END ASC 

结果

╔════╦════════════╦════╗
║ ID ║   Value    ║ rn ║
╠════╬════════════╬════╣
║ 10 ║ ABCDEFGIJK ║  1 ║
║  9 ║ ABCDEFGIJ  ║  1 ║
║  8 ║ ABCDEFGI   ║  1 ║
║  7 ║ ABCDEFG    ║  1 ║
║  6 ║ ABCDEF     ║  1 ║
║  1 ║ A          ║  2 ║
║  2 ║ AB         ║  2 ║
║  3 ║ ABC        ║  2 ║
║  4 ║ ABCD       ║  2 ║
║  5 ║ ABCDE      ║  2 ║
╚════╩════════════╩════╝

Answer 3

这里有一个简短的方法可以帮助您入门：

WITH cte AS
(
    SELECT TOP 1000 number
    FROM master..spt_values 
    WHERE type = 'P' and number >0
)
SELECT number,  row_number() OVER(ORDER BY CASE WHEN number %2 = 1 THEN number ELSE -(number) END) pos 
FROM cte