Question

我有一列包含ASCII精简数字，无论如何将其转换为string(text)？例如，我在一列中有114097102097101108，而我希望下一列是“ rafael”（从ASCII转换为文本）。链接以转换http://www.unit-conversion.info/texttools/ascii/。

Answer 1

如果我理解正确，则可以使用递归CTE：

with cte as (
      select '0' + convert(varchar(max), ascii(left(col, 1))) as rafael, stuff(col, 1, 1, '') as rest, 1 as lev, id, col
      from t
      union all
      select rafael + ' 0' + convert(varchar(max), ascii(left(rest, 1))), stuff(rest, 1, 1, ''), lev + 1, id, col
      from cte
      where rest <> ''
     )
select top (1) with ties id, col, rafael
from cte
order by row_number() over (partition by id order by lev desc);

Here是db <>小提琴。

Answer 2

如果您有更大的字符串，则可以使用计数表的另一种方法：

WITH N AS(
    SELECT N
    FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL)) N(N)),
Tally AS(
    SELECT TOP 8000 ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS I
    FROM N N1, N N2, N N3, N N4),
Parts AS(
    SELECT V.CatNum,
           T.I
    FROM (VALUES('114097102097101108'))V(CatNum)
         JOIN Tally T ON LEN(V.CatNum) >= T.I
    WHERE T.I % 3 = 0)
SELECT V.CatNum,
       (SELECT CHAR(SUBSTRING(P.CatNum,LAG(P.I,1,0) OVER (ORDER BY P.I)+1,3))
        FROM Parts P
        WHERE P.CatNum = V.CatNum
        FOR XML PATH(''),TYPE).value('.','varchar(8000)') AS NewString
FROM (VALUES('114097102097101108'))V(CatNum)

Answer 3

您可以创建一个函数来完成此操作。这将处理最长3万个字符的字符串，并将其转换为1万个字符串。

CREATE FUNCTION dbo.ConvertASCIItoCHAR(
    @String varchar(MAX)
)
RETURNS TABLE WITH SCHEMABINDING
AS RETURN
WITH 
E(n) AS(
    SELECT n FROM (VALUES(0),(0),(0),(0),(0),(0),(0),(0),(0),(0))E(n)
),
E2(n) AS(
    SELECT a.n FROM E a, E b
),
E4(n) AS(
    SELECT a.n FROM E2 a, E2 b
),
cteTally(n) AS(
    SELECT TOP( LEN(@String)/3) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) -1 n
    FROM E4
)
SELECT ( SELECT CHAR(SUBSTRING( @String, n*3+1, 3))
        FROM cteTally
        FOR XML PATH(''), TYPE).value('./text()[1]', 'varchar(max)') AS String

现在您唯一需要做的就是调用该函数。

SELECT c.String
FROM dbo.ConvertASCIItoCHAR( '114097102097101108') c

或

SELECT c.String
FROM SomeTable st
CROSS APPLY dbo.ConvertASCIItoCHAR( st.SomeString) c

将ASCII转换为字符串

3 个答案: