PATINDEX，通配符和变量

Question

你怎么PATINDEX到做对即包括%字符变量的通配符证相符？

在下面我想PATINDEX返回的 '％3D' 的起始位置：

DECLARE @inputText as VARCHAR(100) 
DECLARE @s as Int 
DECLARE @cIn as CHAR(3) 

SET @inputText = 'OEi49j3DNxE%3d' 
SET @cIn = '%3d' 
SET @s = PATINDEX('%' + @cIn +'%', @InputText) 

你可以从@InputText看，这部分起始于12

OEi49j3DNxE ％3d

但是PATINDEX似乎回退R 11在7起始位置，因为它似乎掉落%从CIn：

OEi49j 3D NXE％3D

我要如何找%3d符合规定，而不是3d？

Answer 1

你必须与包裹逃脱％标志[]。为了做到这一点，你必须使你的变量@cIn变大以容纳额外的2个字符，并且在你做patindex之前做一个替换，或者你可以在不改变变量大小的情况下进行内联。

DECLARE @inputText as VARCHAR(100) 
DECLARE @s as Int 
DECLARE @cIn as CHAR(5) 

SET @inputText = 'OEi49j3DNxE%3d' 
SET @cIn = '%3d' 
SET @cIn = REPLACE(@cIn, '%', '[%]') 
SET @s = PATINDEX('%' + @cIn +'%', @InputText) 

OR

DECLARE @inputText as VARCHAR(100) 
DECLARE @s as Int 
DECLARE @cIn as CHAR(5) 

SET @inputText = 'OEi49j3DNxE%3d' 
SET @cIn = '%3d' 
SET @s = PATINDEX('%' + replace(@cIn, '%', '[%]') +'%', @InputText) 

您可以在此处详细了解：How do I escape a percentage sign in T-SQL?

Answer 2

您可以使用方括号：

SET @cIn = '[%]3d' 

---

select 
    without_brackets = patindex('%'+'%3d'+'%','OEi49j3DNxE%3d') 
, with_brackets = patindex('%'+'[%]3d'+'%','OEi49j3DNxE%3d') 

rextester演示：http://rextester.com/BVA62284

回报：

+------------------+---------------+ 
| without_brackets | with_brackets | 
+------------------+---------------+ 
|    7 |   12 | 
+------------------+---------------+ 

Answer 3

DECLARE @inputText as VARCHAR(100) 
DECLARE @s as Int 
DECLARE @cIn as CHAR(3) 

SET @inputText = 'OEi49j3DNxE%3d' 
SET @cIn = '[%]3d' 
SET @s = PATINDEX('%' + @cIn + '%' , @InputText) 

select @s 

输出：12