How to implement fuzzy query in PHP (graphic code)

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Introduction

• Revealing the essence of PHP fuzzy query technology

Function

• Find relevant users based on the entered keywords

PHP User Queryer Case Analysis

Course Objectives

• Master the application of PHP fuzzy technology

Key points of the course

• The syntax of PHP fuzzy query

• PHP fuzzy query application

Course case (rendering)

Database design

User table ( user):

CREATE TABLE user(    
`uid` int(10) AUTO_INCREMENT PRIMARY KEY COMMENT '用户ID',    
`username` varchar(30) NOT NULL DEFAULT '' COMMENT '用户名',    
`password` varchar(6) NOT NULL DEFAULT '' COMMENT '密码',    
`sex` char(2) NOT NULL DEFAULT '保密' COMMENT '性别',    
`email` varchar(40) NOT NULL DEFAULT '' COMMENT '邮箱',    
`hobby` varchar(255) NOT NULL DEFAULT '' COMMENT '兴趣爱好',    
KEY `username`(`username`)//索引
)ENGINE=MyISAM DEFAULT CHARSET=UTF8 COMMENT='用户表'

Benefits of indexing:
If you retrieve data according to a certain condition, if the condition field is not indexed, the entire table will be traversed when querying. If you create an index, the query will be based on the index, thereby improving query performance

Mysql fuzzy query syntax

• SQL matching mode (the most commonly used one in development)

• Regular expression matching Pattern

SQL matching pattern

• #Use SQL matching pattern, you cannot use operator = or !=, but use operator LIKE or NOT LIKE

• Use SQL matching mode, MYSQL provides two wildcard characters:
  ①% represents any number of any characters (including 0)
  ② Any single character represented by _

• ## uses the SQL matching mode. If the matching format does not contain either of the above two wildcard characters, the query effect is equivalent to = or !=

• Use SQL matching pattern, case insensitive by default

代码实现:
SELECT * FROM user WHERE username like 'l%';
SELECT * FROM user WHERE username like '%e';
SELECT * FROM user WHERE username like '%o%';
SELECT * FROM user WHERE username like '___';//三个_，表示username为三个字符的结果集
SELECT * FROM user WHERE username like '_o%';//第二个字符为o

Regular expression matching pattern

• . Matches any single character

• * Matches 0 or more characters before it

eg:x* 表示匹配任何数量的x字符

• [] matches any characters in brackets

eg:[abc] 匹配字符a、b后者c
   [a-z] 匹配任何字母   
   [0-9] 匹配任何数字   
   [0-9]* 匹配任何数量的任何数字   
   [a-z]* 匹配任何数量的任何字母

• ^ means it starts with a certain character or string

eg:^a 表示以字母a开头

• $ represents a certain character or string result

eg：s$ 表示以字母s结尾

• Use regular expressions Operators used in matching patterns: REGEXP(RLIKE) or NOT REGEXP(NOT RLIKE)

code:SELECT * FROM user WHERE username REGEXP '^l';
SELECT * FROM user WHERE username REGEXP '...';

PS: If only the . wildcard is used, there are several dot wildcards, assuming N , then the matching pattern means greater than or equal to N

##The exact number of characters

• ^...$          //表示只能为三个字符
  SELECT * FROM user WHERE username REGEXP '^...$';

Case

Development process

Source code analysis

<?php
//关键字
$keywords = isset($_POST[&#39;keywords&#39;])?$_POST[&#39;keywords&#39;]:&#39;&#39;;
//连接数据库，php7废弃了mysql_connect推荐使用
mysqli_connect$link = mysqli_connect(    "localhost:3306",    "root",    "root",    "mook");
if(!empty($keywords)){    
$sql = "SELECT * FROM user WHERE username like &#39;%{$keywords}%&#39; ";
}else{    
$sql = "SELECT * FROM user";
}$usersArr = [];$result = $link->query($sql);while($row = $result->fetch_assoc())
{    //简单高亮显示
    // $row[&#39;username&#39;] = str_replace($keywords, "<font color=&#39;red&#39;>".$keywords."</font>",$row[&#39;username&#39;]);
    //高亮显示，不区分关键字的大小写
    $usernameArr = preg_split(&#39;/(?<!^)(?!$)/u&#39;,$row[&#39;username&#39;]);    
    foreach ($usernameArr as $key => $value) {        
    if(strtoupper($keywords) == strtoupper($value)){            
    $usernameArr[$key] = "<font color=&#39;red&#39;>".$value."</font>";
        }
    }    
    $row[&#39;username&#39;] = join($usernameArr);    
    $usersArr[] = $row;
}?><!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>php用户查询器</title>
</head>
<body>
    <h1 id="php模糊查询">php模糊查询</h1>
    <form action="index.php" method="post">
        用户名:<input type="text" name="keywords" value="" />
        <input type="submit" value="提交查询" />
    </form>    
    <?php
        if(!empty($keywords)){            
        echo "查询关键词:<font color=&#39;red&#39;> ".$keywords." </font>结果!";
        }        
        $tableString = "<table width=&#39;500&#39; border=&#39;1&#39; cellpadding=&#39;5&#39;>";        
        $tableString .= "<tr bgcolor=&#39;orange&#39;><th>用户名</th><th>邮箱</th><th>性别</th></tr>";        
        if(!empty($usersArr)){           
         foreach ($usersArr as $key => $value) {                
        $tableString .= "<tr><td>" . $value[&#39;username&#39;]. "</td><td>" . $value[&#39;email&#39;] . "</td><td>".$value[&#39;sex&#39;]."</td></tr>";
            }
        }else{           
         $tableString .="<tr><td colspan=&#39;3&#39;>没有数据</td></tr>";
        }        
        $tableString .= "</table>";        
        echo $tableString;    
        ?>
        </body>
</html>

Source code download address:

Link ：https://pan.baidu.com/s/1F8duu8G2iCa4xgNLBbiLCg Password: 96fn

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