Question

我试图重写以下代码以使用变量而不是幻数：

SELECT tokenId, 
IIF(LEN(ref) < 4, ref, REPLICATE(CONVERT(NVARCHAR(20),'*'), LEN(ref)-4) + SUBSTRING(ref, (LEN(ref)-3), LEN(ref))) as refMasked
FROM tokenBase
WHERE (refMasked is null or refMasked = '') AND ref is not null AND ref <> ''

我尝试这样做：

DECLARE @NumberOfCharsAtEndOfStringToNotMask INTEGER
SET @NumberOfCharsAtEndOfStringToNotMask = 4 --Why do I need to set this to 2 for it to work?
SELECT tokenId, 
IIF(LEN(ref) < @NumberOfCharsAtEndOfStringToNotMask, ref, REPLICATE(CONVERT(NVARCHAR(20),'*'), LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask) + SUBSTRING(ref, (LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask-1), LEN(ref))) as refMasked
FROM   tokenBase
WHERE  (refMasked is null or refMasked = '') AND ref is not null AND ref <> ''

但是如果我使用@NumberOfCharsAtEndOfStringToNotMask = 4它不起作用，我需要使用2代替。为什么是这样？如果我使用4，那么字符串的最后6个字符将被取消屏蔽，但是我需要将最后4个字符取消屏蔽。使用值2修复此问题，但我不明白为什么。

修改 Amit建议我使用以下代码：

IIF(LEN(ref) < @NumberOfCharsAtEndOfStringToNotMask, ref,REPLICATE(CONVERT(NVARCHAR(20),'*'), LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask) + SUBSTRING(ref, (LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask+1),@NumberOfCharsAtEndOfStringToNotMask)) as refMasked

为什么这样做？为什么我不能用存储4的值的变量替换4的使用？

Answer 1

将iif块替换为此块，看看你如何进行

IIF(LEN(ref) < @NumberOfCharsAtEndOfStringToNotMask, ref,REPLICATE(CONVERT(NVARCHAR(20),'*'), LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask) + SUBSTRING(ref, (LEN(ref)-@NumberOfCharsAtEndOfStringToNotMask+1),@NumberOfCharsAtEndOfStringToNotMask)) as refMasked

Answer 2

试试这个戴夫：

DECLARE @C INTEGER = 4;

SELECT bpayreference 
     , LEN(bpayreference) As LengthOfString
     , LEN(bpayreference) - @C AS MinusC
     , SUBSTRING(bpayreference , (LEN(bpayreference) - @C) + 1 , (LEN(bpayreference) ) - (LEN(bpayreference) - @C))
     , CASE 
       WHEN (LEN(bpayreference) < @C) THEN REPLICATE('*' , LEN(bpayreference) - @C) 
       ELSE 
               REPLICATE('*' , LEN(bpayreference) - @C ) 
             + SUBSTRING(bpayreference , (LEN(bpayreference) - @C) + 1 , (LEN(bpayreference) ) - (LEN(bpayreference) - @C))
       END
FROM tokenbase

SQL变量更改值

2 个答案: