將字符串的所有字符替換爲MSSQL中第一個字符和空格以外的星號

Question

我很疑惑是否可以通過函數對mssql中的敏感數據進行哈希處理，併爲所有字段保留「原樣」的第一個字符。例如：

「喬恩·柯克」的名字應該被提取爲J **畝***

Answer 1

我已經發布了一個遞歸解決方案首先這是更快：

declare @name varchar(20) = 'Jon Kirk' 

declare @loop int = len(@name) 

while @loop > 1 
select @name = stuff(@name, @loop, 1, 
case when substring(@name, @loop-1,2) like '% ' then ' ' 
    when substring(@name, @loop-1,2) like ' %' then substring(@name, @loop,1) 
else '*' end), @loop+=-1 

select @name 

Answer 2

如何像這樣

declare @s varchar(50) = 'Jon kirk' 

;with cte as (
    select 1 as i, cast (' ' + ltrim (@s) as varchar(50)) as s 
    union all 
    select i + 1 
     , cast (
      case when substring (s, i, 2) like '% %' 
      then s 
      else stuff (s, i + 1, 1, '*') end 
     as varchar(50)) 
    from cte 
    where i < len (s) 
) 

select top 1 ltrim (s) as s 
from cte 
order by i desc 

這裏是最快的解決方案（雖然不是很漂亮嗎？在所有）：

declare @s varchar(50) = 'Jon kirk' 

select left (
     left (@s, 1) 
    + case when substring (@s, 1, 2) like '% %' then substring (@s, 2, 1) else '*' end 
    + case when substring (@s, 2, 2) like '% %' then substring (@s, 3, 1) else '*' end 
    + ... 
    + case when substring (@s, 48, 2) like '% %' then substring (@s, 49, 1) else '*' end 
    + case when substring (@s, 49, 2) like '% %' then substring (@s, 50, 1) else '*' end 
    , len (@s))