SQL 服务器比较数据并一起替换

Question

我有如下两个字符串：

 ***ABCABCABCABCABC***
 BBBTTTTTTTTTTTTTTTCCC

我只想从字符串下方替换 * 位置

所以结果可能是：

 BBBABCABCABCABCABCCCC
 BBBTTTTTTTTTTTTTTTCCC

有什么方法可以优雅地解决使用 SQL 服务器功能的问题吗？

我已经用下面的方法做到了。

 DECLARE @Value1=PATINDEX('%[A,C,G,T]%', '***ABCABCABCABCABC***')
 Select SUBSTRING('BBBTTTTTTTTTTTTTTTBBB', 0, @Value1)
 ....

但这需要很多if else。

我想知道有没有简单的方法可以替换它

Answer 1

您可以使用：

DEMO

DECLARE
   @String1 NVARCHAR(100) = '***ABCABCABCABCABC***',
   @String2 NVARCHAR(100) = 'BBBTTTTTTTTTTTTTTTCCC';

DECLARE @new_string NVARCHAR(100) = NULL;

;WITH nums AS
(
  SELECT TOP 1000 ROW_NUMBER() OVER(ORDER BY t1.number) AS N
  FROM master..spt_values t1 
  CROSS JOIN master..spt_values t2
), string_1 AS
(
  SELECT N, letter
  FROM nums
  CROSS APPLY (SELECT SUBSTRING(@String1, nums.N, 1) WHERE nums.N <= LEN(@String1)) 
    AS t(letter)
), string_2 AS
(
  SELECT N, letter
  FROM nums
  CROSS APPLY (SELECT SUBSTRING(@String2, nums.N, 1) WHERE nums.N <= LEN(@String2)) 
   AS t(letter)
), new_string AS
(
  SELECT Letter = CASE WHEN s1.Letter <> '*' THEN s1.Letter ELSE s2.Letter END,
         s1.N
  FROM string_1 s1
  LEFT JOIN string_2 s2
    ON s1.N = s2.N
)
SELECT @new_string = (SELECT '' + ISNULL(Letter, '')
                      FROM new_string
                      ORDER BY N ASC
                      FOR XML PATH(''));
                            
SELECT @new_string
UNION ALL
SELECT @String2;

生成数字（可以使用任何方法）
按字母拆分字符串一和二
生成新字符串，将*替换为相应的字母
将字母连接在一起

备注：您可以将所有这些组合在一个查询中，但为了便于阅读，我将其拆分。

随意包装它以使其发挥作用优雅:

[dbo].[udf_merge_string](@string NVARCHAR(100), @string2 NVARCHAR(100)) ...

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