PHP connects to MYSQL database

Because a certain project required PHP to connect to MySql two days ago. Although I learned it before, I have basically forgotten it now. However, I later found a method by searching a lot of information:

<?<span>php
    </span><span>//</span><span>设置字符集</span><span>header</span>('Content-Type: text/html; charset=utf8'<span>);

    </span><span>//</span><span>连接数据库</span><span>$link</span> = <span>mysql_connect</span>("localhost","root","123456"<span>);

    </span><span>if</span>(!<span>$link</span><span>){
        </span><span>echo</span> '数据库连接失败...<br>'<span>;
        </span><span>exit</span>(-1<span>);
    }</span><span>else</span><span>{
        </span><span>echo</span> "数据库连接成功...<br>"<span>;
    }

    </span><span>//</span><span>选择一个数据库作为默认数据库</span><span>mysql_select_db</span>('php_sjk'<span>);

    </span><span>//</span><span>执行sql插入语句</span><span>$sql</span> = "INSERT INTO zh VALUES (NULL,'王杰','123456')"<span>;
    </span><span>$cr</span> = <span>mysql_query</span>(<span>$sql</span><span>);

    </span><span>//</span><span>判断是否插入成功</span><span>if</span>(!<span>$cr</span><span>){
        </span><span>echo</span> "数据插入失败。<br>"<span>;
    }</span><span>else</span><span>{
        </span><span>echo</span> "数据插入成功。<br>"<span>;
    }
    
    </span><span>//</span><span>执行sql查询语句</span><span>$sql</span> = "select * from zh"<span>;
    </span><span>$cr</span> = <span>mysql_query</span>(<span>$sql</span><span>);
    
    </span><span>//</span><span>得到返回的结果集,并循环输出</span><span>echo</span> "数据展示：<br><br><br>"<span>;
    </span><span>while</span>(<span>$a</span> = <span>mysql_fetch_row</span>(<span>$cr</span><span>)){
        </span><span>echo</span> "{<span>$a</span>[0]}——{<span>$a</span>[1]}——{<span>$a</span>[2]}<br>"<span>;
    }

    </span><span>//</span><span>关闭数据库连接</span><span>mysql_close</span>(<span>$link</span><span>);
</span>?>

The above introduces PHP to connect to the MYSQL database, including aspects of the content. I hope it will be helpful to friends who are interested in PHP tutorials.