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  • PHP+MySQL

    链接和关闭

    <?php
        //强制显示utf-8
        header("Content-type: text/html; charset=utf-8"); 
        $servername = "localhost";
        $username = "root";
        $password = "";
    
        $con = mysql_connect($servername,$username,$password);
        // 检测连接
        if (!$con) {
            die("Connection failed: " . mysql_error());
        } 
        echo "数据库链接成功";
        mysql_close($con);
        echo "数据库关闭";
    ?>

    创建数据库&创建表

    <?php
        //强制显示utf-8
        header("Content-type: text/html; charset=utf-8"); 
        $servername = "localhost";
        $username = "root";
        $password = "";
    
        $con = mysql_connect($servername,$username,$password);
        // 检测连接
        if (!$con) {
            die("Connection failed: " . mysql_error());
        } 
        //创建数据库
        if (mysql_query("CREATE DATABASE my_db",$con)) {
            # code...
            echo "Database create";
        }else {
            echo "Error createing database:".mysql_error();
        }
        //create table in my_db database
        mysql_select_db("my_db",$con);
        //创建了主键和需要的字段
        $sql = "CREATE TABLE Person
        (
            personID int NOT NULL primary key AUTO_INCREMENT, 
            FirstName varchar(15),
            LastName varchar(15),
            Age int
        )";
        mysql_query($sql,$con);
        mysql_close($con);
        echo "<br>执行完成-数据库关闭";
    
    ?>

    MySQL数据类型

     

    插入数据

    <?php
        //强制显示utf-8
        header("Content-type: text/html; charset=utf-8"); 
        $servername = "localhost";
        $username = "root";
        $password = "";
    
        $con = mysql_connect($servername,$username,$password);
        // 检测连接
        if (!$con) {
            die("Connection failed: " . mysql_error());
        } 
        //创建数据库
        if (mysql_query("CREATE DATABASE my_db",$con)) {
            # code...
            echo "Database create";
        }else {
            echo "Error createing database:".mysql_error();
        }
        //create table in my_db database
        mysql_select_db("my_db",$con);
        //创建了主键和需要的字段
        mysql_query("INSERT INTO Person (FirstName,LastName,Age)
            Values ('Glenn1','Quagmire','33')");
        mysql_query("INSERT INTO Person (FirstName,LastName,Age)
            Values ('aaaaa','bbbb','10')");
        mysql_close($con);
        echo "<br>执行完成-数据库关闭";
    
    ?>

    使用表单插入数据

    post.php

    <html>
    <body>
    
    <form action="dbtest.php" method="post">
    Firstname: <input type="text" name="firstname" />
    Lastname: <input type="text" name="lastname" />
    Age: <input type="text" name="age" />
    <input type="submit" />
    </form>
    
    </body>
    </html>

    dbtest.php

    <?php
        //强制显示utf-8
        header("Content-type: text/html; charset=utf-8"); 
        $servername = "localhost";
        $username = "root";
        $password = "";
    
        $con = mysql_connect($servername,$username,$password);
        // 检测连接
        if (!$con) {
            die("Connection failed: " . mysql_error());
        } 
        //创建数据库
        if (mysql_query("CREATE DATABASE my_db",$con)) {
            # code...
            echo "Database create";
        }else {
            echo "Error createing database:".mysql_error()."<br>";
        }
        //create table in my_db database
        mysql_select_db("my_db",$con);
    
        $sql = "INSERT INTO Person (FirstName,LastName,Age) 
            VALUES ('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
        if (!mysql_query($sql,$con)) {
            # code...
            die('Error:'.mysql_error());
        }
        echo "添加了一条数据";
        mysql_close($con);
        echo "<br>执行完成-数据库关闭";
    
    ?>

    查询

    <?php
        //强制显示utf-8
        header("Content-type: text/html; charset=utf-8"); 
        $servername = "localhost";
        $username = "root";
        $password = "";
    
        $con = mysql_connect($servername,$username,$password);
        // 检测连接
        if (!$con) {
            die("Connection failed: " . mysql_error());
        } 
        //创建数据库
        if (mysql_query("CREATE DATABASE my_db",$con)) {
            # code...
            echo "Database create";
        }else {
            echo "Error createing database:".mysql_error()."<br>";
        }
        // table in my_db database
        mysql_select_db("my_db",$con);
    
        $result = mysql_query("SELECT * FROM Person");
    
        while ($row = mysql_fetch_array($result)) {
            # code...
            echo "姓名:".$row['FirstName']."   ".$row['LastName'];
            echo "<br>";
        }
    
        mysql_close($con);
        echo "<br>执行完成-数据库关闭";
    
    ?>

    条件查询

    运算符

    $result = mysql_query("SELECT * FROM Person WHERE FirstName = 'aaaaa' ");

    排序

    默认升序

    $result = mysql_query("SELECT * FROM Persons ORDER BY age");

    使用 DESC 关键词来设定降序排序(9 在 1 之前,"p" 在 "a" 之前):

    SELECT column_name(s)
    FROM table_name
    ORDER BY column_name DESC

    可以根据多个列进行排序。当按照多个列进行排序时,只有第一列相同时才使用第二列:

    SELECT column_name(s)
    FROM table_name
    ORDER BY column_name1, column_name2

    更新数据

    UPDATE table_name
    SET column_name = new_value
    WHERE column_name = some_value
    $sql = mysql_query("UPDATE Person SET Age = '100' WHERE FirstName = 'aaaaa'");

    删除数据

    DELETE FROM table_name
    WHERE column_name = some_value
    $sql = mysql_query("DELETE FROM Person WHERE FirstName = '11'");
    PHP是世界上最好的语言
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  • 原文地址:https://www.cnblogs.com/proginn/p/5587893.html
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