问题描述
我试图找出从字符串开头删除字符时的最佳做法.
I'm trying to find out the best practice when removing characters from the start of a string.
在某些语言中,您可以使用不带长度参数的 MID,但在 TSQL 中需要长度.
In some languages, you can use MID without a length parameter however, in TSQL the length is required.
考虑以下代码,最佳实践是什么?(十六进制字符串是可变长度的)
Considering the following code, what is the best practise? (The hex string is variable length)
DECLARE @sHex VARCHAR(66)
SET @sHex = '0x7E260F3DA734AD4BD816B88F485CE501D843DF067C8EDCB8AC7DAD331852E04D'
PRINT RIGHT(@sHex,LEN(@sHex) -2)
PRINT SUBSTRING(@sHex,3,LEN(@sHex) -2)
PRINT SUBSTRING(@sHex,3,65535)
推荐答案
嗯,第一个更能表达您的意图.最后一个显然是混乱的(硬编码长度等).我怀疑你会发现第一个 & 之间有很大的性能差异.第二,所以我会使用最简单的 - RIGHT
.
Well, the first is more expressive of your intent. The last is clearly messy (hard-coded length etc). I doubt you'd find much performance difference between the first & second, so I'd use the simplest - RIGHT
.
当然,如果你做了这么多,你可以写一个 udf 来封装这个——那么如果你改变主意,你只有一个地方可以改变......
Of course, if you are doing this lots, you could write a udf that encapsulates this - then if you change your mind you only have one place to change...
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