SQL Server截取字符串和处理中文技巧

待我称王封你为后i 2022-08-27 01:22 259阅读 0赞

## 一 环境介绍 ##

>     SQL  Server
>     
>     PRINT @@VERSION
>     MicrosoftSQLServer2012-11.0.2100.60(X64)
>     Feb10201219:39:15
>     Copyright(c)MicrosoftCorporation
>     EnterpriseEdition:Core-basedLicensing(64-bit)onWindowsNT6.1(Build7601:ServicePack1)
>     
>     操作系统
>     ------------------
>     System Information
>     ------------------
>     Operating System: Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130828-1532)
>     System Model: Aspire E1-471G
>     Processor: Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz (4 CPUs), ~2.6GHz
>     Memory: 4096MB RAM

## 二 实现功能 ##

从一大堆有包含中文字符和编号的字符串中过滤出编号。

## 三 实现模拟 ##

首先，我们准备测试数据，注意，这里的数据全部都是模拟数据，无实际含义。语句如下：

CREATE TABLE #temp
    (
       name VARCHAR(80)
    );
    
    INSERT INTO #temp
    VALUES     ('五道口店3059');
    
    INSERT INTO #temp
    VALUES     ('五羊邨店3060');
    
    INSERT INTO #temp
    VALUES     ('杨家屯店3061');
    
    INSERT INTO #temp
    VALUES     ('十里堤店3062');
    
    INSERT INTO #temp
    VALUES     ('中关村店3063');
    
    INSERT INTO #temp
    VALUES     ('丽秀店3064');
    
    INSERT INTO #temp
    VALUES     ('石门店3065');
    
    INSERT INTO #temp
    VALUES     ('黄村店3066');
    
    INSERT INTO #temp
    VALUES     ('东圃店3067');
    
    INSERT INTO #temp
    VALUES     ('天河店3068');
    
    INSERT INTO #temp
    VALUES     ('人民路广场3069');
    
    INSERT INTO #temp
    VALUES     ('社区中心3070');
    
    INSERT INTO #temp
    VALUES     ('珠海市3071');
    
    INSERT INTO #temp
    VALUES     ('丽都3072');
    
    INSERT INTO #temp
    VALUES     ('晓月3073');
    
    INSERT INTO #temp
    VALUES     ('旧区3074');
    
    INSERT INTO #temp
    VALUES     ('新城3075');
    
    INSERT INTO #temp
    VALUES     ('水井沟3076');

然后，我们观察数据，发现这些数据都有规律，编号是数字，占4个字符。数字前面包含店、场、心、市、都、月、区、城、沟共9个字符。  
我们试着采用SQL Server内置的函数Substring、Charindex、Rtrim、Ltrim过滤掉出现次数最多（店）的字符串。  
语句如下：

SELECT Rtrim(Ltrim(Substring(name, Charindex('店', name) + 1, Len(name)))) AS name
    INTO   #t1
    FROM   #temp

以下是这几个函数的使用说明：

**Substring**

Returns the part of a character expression that starts at the specified position and has the specified length. The position parameter and the length parameter must evaluate to integers.

**Syntax**

SUBSTRING(character\_expression, position, length)

**Arguments**

character\_expression

Is a character expression from which to extract characters.

position

Is an integer that specifies where the substring begins.

length

Is an integer that specifies the length of the substring as number of characters.

**Result Types**

DT\_WSTR

**Charindex**  
Searches an expression for another expression and returns its starting position if found.  
  
**Syntax**

CHARINDEX ( expressionToFind ,expressionToSearch \[ , start\_location \] )

**Arguments**  
expressionToFind  
Is a character expression that contains the sequence to be found. expressionToFind is limited to 8000 characters.  
expressionToSearch  
Is a character expression to be searched.  
start\_location  
Is an integer or bigint expression at which the search starts. If start\_location is not specified, is a negative number, or is 0, the search starts at the beginning of expressionToSearch.  
  
**Return Types**  
bigint if expressionToSearch is of the varchar(max), nvarchar(max), or varbinary(max) data types; otherwise, int.  
  
**Rtrim**  
Returns a character expression after removing trailing spaces.  
  
RTRIM does not remove white space characters such as the tab or line feed characters. Unicode provides code points for many different types of spaces, but this function recognizes only the Unicode code point 0x0020. When double-byte character set (DBCS) strings are converted to Unicode they may include space characters other than 0x0020 and the function cannot remove such spaces. To remove all kinds of spaces, you can use the Microsoft Visual Basic .NET RTrim method in a script run from the Script component.  
  
**Syntax**  
RTRIM(character expression)  
                
**Arguments**  
character\_expression  
Is a character expression from which to remove spaces.  
  
**Result Types**  
DT\_WSTR  
  
**Ltrim**  
Returns a character expression after removing leading spaces.  
  
LTRIM does not remove white-space characters such as the tab or line feed characters. Unicode provides code points for many different types of spaces, but this function recognizes only the Unicode code point 0x0020. When double-byte character set (DBCS) strings are converted to Unicode they may include space characters other than 0x0020 and the function cannot remove such spaces. To remove all kinds of spaces, you can use the Microsoft Visual Basic .NET LTrim method in a script run from the Script component.  
  
**Syntax**  
LTRIM(character expression)  
                
**Arguments**  
character\_expression  
Is a character expression from which to remove spaces.  
  
**Result Types**  
DT\_WSTR  
  
好了，我们查看处理完后的结果，可以看到包含店的字符串已经全部过滤出编号。

SELECT * FROM #t1
    
    
    3059
    3060
    3061
    3062
    3063
    3064
    3065
    3066
    3067
    3068
    人民路广场3069
    社区中心3070
    珠海市3071
    丽都3072
    晓月3073
    旧区3074
    新城3075
    水井沟3076

接着我们依次处理包含场、心、市、都、月、区、城、沟的字符串，语句和处理结果如下：

SELECT *
    FROM   #t1
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    人民路广场3069
    社区中心3070
    珠海市3071
    丽都3072
    晓月3073
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('场', name) + 1, Len(name)))) AS name
    INTO   #t2
    FROM   #t1
    
    
    SELECT *
    FROM   #t2
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    社区中心3070
    珠海市3071
    丽都3072
    晓月3073
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('心', name) + 1, Len(name)))) AS name
    INTO   #t3
    FROM   #t2
    
    
    SELECT *
    FROM   #t3
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    珠海市3071
    丽都3072
    晓月3073
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('市', name) + 1, Len(name)))) AS name
    INTO   #t4
    FROM   #t3
    
    
    SELECT *
    FROM   #t4
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    丽都3072
    晓月3073
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('都', name) + 1, Len(name)))) AS name
    INTO   #t5
    FROM   #t4
    
    
    SELECT *
    FROM   #t5
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    晓月3073
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('月', name) + 1, Len(name)))) AS name
    INTO   #t6
    FROM   #t5
    
    
    SELECT *
    FROM   #t6
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    旧区3074
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('区', name) + 1, Len(name)))) AS name
    INTO   #t7
    FROM   #t6
    
    
    SELECT *
    FROM   #t7
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    新城3075
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('城', name) + 1, Len(name)))) AS name
    INTO   #t8
    FROM   #t7
    
    
    SELECT *
    FROM   #t8
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    水井沟3076
    
    
    SELECT Rtrim(Ltrim(Substring(name, Charindex('沟', name) + 1, Len(name)))) AS name
    INTO   #t9
    FROM   #t8
    
    
    SELECT *
    FROM   #t9
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN 
    
    
    --无记录

这是最终的处理结果，过滤出编号后，我就可以利用这些编号和数据库表进行关联，获得想要的数据。

SELECT *
    INTO   #result
    FROM   #t9
    
    
    SELECT *
    FROM   #result 
    
    
    name
    3059
    3060
    3061
    3062
    3063
    3064
    3065
    3066
    3067
    3068
    3069
    3070
    3071
    3072
    3073
    3074
    3075
    3076
    
    
    SELECT s.xxx,
           s.xxx
    FROM   xx s
           JOIN #result r
             ON s.xxx = r.name
    WHERE  s.xxx = 0;

## 四 总结 ##

本文过滤编号实际上核心代码就两个，第一个是利用SQL Server的内置函数过滤出指定编号，语句如下：

SELECT Rtrim(Ltrim(Substring(name, Charindex('店', name) + 1, Len(name)))) AS name
    INTO   #t1
    FROM   #temp

第二个是判断是否包含中文，语句如下：

SELECT *
    FROM   #t1
    WHERE  name LIKE N'%[一-龥]%' COLLATE Chinese_PRC_BIN

在工作中，发现和总结这些小技巧会让你的工作事半功倍。

**Good Luck!**