<?php
//header('content-type:text/html;charset=utf-8');
class PdoMySQL{
    public static $config=array();//设置连接参数，配置信息
    public static $link=null;//保存连接标识符
    public static $pconnect=false;//是否开启长连接
    public static $dbVersion=null;//保存数据库版本
    public static $connected=false;//是否连接成功
    public static $PDOStatement=null;//保存PDOStatement对象
    public static $queryStr=null;//保存最后执行的操作
    public static $error=null;//报错错误信息
    public static $lastInsertId=null;//保存上一步插入操作产生AUTO_INCREMENT
    public static $numRows=0;//上一步操作产生受影响的记录的条数
    /**
     * 连接PDO
     * @param string $dbConfig
     * @return boolean
     */
    public function __construct($dbConfig=''){
        if(!class_exists("PDO")){
            self::throw_exception('不支持PDO，请先开启');
        }
        if(!is_array($dbConfig)){
            $dbConfig=array(
                    'hostname'=>DB_HOST,
                    'username'=>DB_USER,
                    'password'=>DB_PWD,
                    'database'=>DB_NAME,
                    'hostport'=>DB_PORT,
                    'dbms'=>DB_TYPE,
                    'dsn'=>DB_TYPE.":host=".DB_HOST.";dbname=".DB_NAME
            );
        }
        if(empty($dbConfig['hostname']))self::throw_exception('没有定义数据库配置，请先定义');
        self::$config=$dbConfig;
        if(empty(self::$config['params']))self::$config['params']=array();
        if(!isset(self::$link)){
            $configs=self::$config;
            if(self::$pconnect){
                //开启长连接，添加到配置数组中
                $configs['params'][constant("PDO::ATTR_PERSISTENT")]=true;
            }
            try{
                self::$link=new PDO($configs['dsn'],$configs['username'],$configs['password'],$configs['params']);
            }catch(PDOException $e){
                self::throw_exception($e->getMessage());
            }
            if(!self::$link){
                self::throw_exception('PDO连接错误');
                return false;
            }
            self::$link->exec('SET NAMES '.DB_CHARSET);
            self::$dbVersion=self::$link->getAttribute(constant("PDO::ATTR_SERVER_VERSION"));
            self::$connected=true;
            unset($configs);
        }
    }

    /**
     * 得到所有记录
     * @param string $sql
     * @return unknown
     */
    public static function getAll($sql=null){
        if($sql!=null){
            self::query($sql);
        }
        $result=self::$PDOStatement->fetchAll(constant("PDO::FETCH_ASSOC"));
        return $result;
    }
    /**
     * 得到结果集中的一条记录
     * @param string $sql
     * @return mixed
     */
    public static function getRow($sql=null){
        if($sql!=null){
            self::query($sql);
        }
        $result=self::$PDOStatement->fetch(constant("PDO::FETCH_ASSOC"));
        return $result;
    }
    /**
     * 根据主键查找记录
     * @param string $tabName
     * @param int $priId
     * @param string $fields
     * @return mixed
     */
    public static function findById($tabName,$priId,$fields='*'){
        $sql='SELECT %s FROM %s WHERE id=%d';
        return self::getRow(sprintf($sql,self::parseFields($fields),$tabName,$priId));
    }

    /**
     * 执行普通查询
     * @param unknown $tables
     * @param string $where
     * @param string $fields
     * @param string $group
     * @param string $having
     * @param string $order
     * @param string $limit
     * @return Ambigous <unknown, unknown, multitype:>
     */
    public static function find($tables,$where=null,$fields='*',$group=null,$having=null,$order=null,$limit=null){
        $sql='SELECT '.self::parseFields($fields).' FROM '.'`'.$tables.'`'
                .self::parseWhere($where)
                .self::parseGroup($group)
                .self::parseHaving($having)
                .self::parseOrder($order)
                .self::parseLimit($limit);
//      echo $sql;
        $dataAll=self::getAll($sql);
//      return count($dataAll)==1?$dataAll[0]:$dataAll;
        return $dataAll;
    }

    /**
     * 添加记录的操作
     * @param array $data
     * @param string $table
     * @return Ambigous <boolean, unknown, number>
     */
    public static function add($data,$table){
        $keys=array_keys($data);
        array_walk($keys,array('PdoMySQL','addSpecialChar'));
        $fieldsStr=join(',',$keys);
        $values="'".join("','",array_values($data))."'";
        $sql="INSERT INTO `{$table}`({$fieldsStr}) VALUES({$values})";
//      echo $sql;
        return self::execute($sql);
    }

    /**
     * 更新记录
     * @param array $data
     * @param string $table
     * @param string $where
     * @param string $order
     * @param string $limit
     * @return Ambigous <boolean, unknown, number>
     */
    public static function update($data,$table,$where=null,$order=null,$limit=0){
        foreach($data as $key=>$val){
            $sets.="`".$key."`='".$val."',";
        }
        $sets=rtrim($sets,',');
        $sql="UPDATE {$table} SET {$sets} ".self::parseWhere($where).self::parseOrder($order).self::parseLimit($limit);
//      echo $sql;
        return self::execute($sql);
    }
    /**
     * 删除记录的操作
     * @param string $table
     * @param string $where
     * @param string $order
     * @param number $limit
     * @return Ambigous <boolean, unknown, number>
     */
    public static function delete($table,$where=null,$order=null,$limit=0){
        $sql="DELETE FROM `{$table}` ".self::parseWhere($where).self::parseOrder($order).self::parseLimit($limit);
        return self::execute($sql);
    }

    /**
     *
     */
    public static function truncate($table){
        $sql="TRUNCATE TABLE `{$table}` ";
        return self::execute($sql);
    }

    /**
     * 得到最后执行的SQL语句
     * @return boolean|Ambigous <string, string>
     */
    public static function getLastSql(){
        $link=self::$link;
        if(!$link)return false;
        return self::$queryStr;
    }
    /**
     * 得到上一步插入操作产生AUTO_INCREMENT
     * @return boolean|string
     */
    public static function getLastInsertId(){
        $link=self::$link;
        if(!$link)return false;
        return self::$lastInsertId;
    }
    /**
     * 得到数据库的版本
     * @return boolean|mixed
     */
    public static function getDbVerion(){
        $link=self::$link;
        if(!$link)return false;
        return self::$dbVersion;
    }
    /**
     * 得到数据库中数据表
     * @return multitype:mixed
     */
    public static function showTables(){
        $tables=array();
        if(self::query("SHOW TABLES")){
            $result=self::getAll();
            foreach($result as $key=>$val){
                $tables[$key]=current($val);
            }
        }
        return $tables;
    }
    /**
     * 解析Where条件
     * @param unknown $where
     * @return string
     */
    public static function parseWhere($where){
        $whereStr='';
        if(is_string($where)&&!empty($where)){
            $whereStr=$where;
        }
        return empty($whereStr)?'':' WHERE '.$whereStr;
    }
    /**
     * 解析group by
     * @param unknown $group
     * @return string
     */
    public static function parseGroup($group){
        $groupStr='';
        if(is_array($group)){
            $groupStr.=' GROUP BY '.implode(',',$group);
        }elseif(is_string($group)&&!empty($group)){
            $groupStr.=' GROUP BY '.$group;
        }
        return empty($groupStr)?'':$groupStr;
    }
    /**
     * 对分组结果通过Having子句进行二次删选
     * @param unknown $having
     * @return string
     */
    public static function parseHaving($having){
        $havingStr='';
        if(is_string($having)&&!empty($having)){
            $havingStr.=' HAVING '.$having;
        }
        return $havingStr;
    }
    /**
     * 解析Order by
     * @param unknown $order
     * @return string
     */
    public static function parseOrder($order){
        $orderStr='';
        if(is_array($order)){
            $orderStr.=' ORDER BY '.join(',',$order);
        }elseif(is_string($order)&&!empty($order)){
            $orderStr.=' ORDER BY '.$order;
        }
        return $orderStr;
    }
    /**
     * 解析限制显示条数limit
     * limit 3
     * limit 0,3
     * @param unknown $limit
     * @return unknown
     */
    public static function parseLimit($limit){
        $limitStr='';
        if(is_array($limit)){
            if(count($limit)>1){
                $limitStr.=' LIMIT '.$limit[0].','.$limit[1];
            }else{
                $limitStr.=' LIMIT '.$limit[0];
            }
        }elseif(is_string($limit)&&!empty($limit)){
            $limitStr.=' LIMIT '.$limit;
        }
        return $limitStr;
    }
    /**
     * 解析字段
     * @param unknown $fields
     * @return string
     */
    public static function parseFields($fields){
        if(is_array($fields)){
            array_walk($fields,array('PdoMySQL','addSpecialChar'));
            $fieldsStr=implode(',',$fields);
        }elseif(is_string($fields)&&!empty($fields)){
            if(strpos($fields,'`')===false){
                $fields=explode(',',$fields);
                array_walk($fields,array('PdoMySQL','addSpecialChar'));
                $fieldsStr=implode(',',$fields);
            }else{
                $fieldsStr=$fields;
            }
        }else{
            $fieldsStr='*';
        }
        return $fieldsStr;
    }
    /**
     * 通过反引号引用字段，
     * @param unknown $value
     * @return string
     */
    public static function addSpecialChar(&$value){
        if($value==='*'||strpos($value,'.')!==false||strpos($value,'`')!==false){
            //不用做处理
        }elseif(strpos($value,'`')===false){
            $value='`'.trim($value).'`';
        }
        return $value;
    }
    /**
     * 执行增删改操作，返回受影响的记录的条数
     * @param string $sql
     * @return boolean|unknown
     */
    public static function execute($sql=null){
        $link=self::$link;
        if(!$link) return false;
        self::$queryStr=$sql;
        if(!empty(self::$PDOStatement))self::free();
        $result=$link->exec(self::$queryStr);
        self::haveErrorThrowException();
        if($result || $result==0){
            self::$lastInsertId=$link->lastInsertId();
            self::$numRows=$result;
            return self::$numRows;
        }else{
            return false;
        }
    }
    /**
    释放结果集
     */
    public static function free(){
        self::$PDOStatement=null;
    }
    public static function query($sql=''){
        $link=self::$link;
        if(!$link) return false;
        //判断之前是否有结果集，如果有的话，释放结果集
        if(!empty(self::$PDOStatement))self::free();
        self::$queryStr=$sql;
        self::$PDOStatement=$link->prepare(self::$queryStr);
        $res=self::$PDOStatement->execute();
        self::haveErrorThrowException();
        return $res;
    }
    public static function haveErrorThrowException(){
        $obj=empty(self::$PDOStatement)?self::$link: self::$PDOStatement;
        $arrError=$obj->errorInfo();
        //print_r($arrError);
        if($arrError[0]!='00000'){
            self::$error='SQLSTATE: '.$arrError[0].' <br/>SQL Error: '.$arrError[2].'<br/>Error SQL:'.self::$queryStr;
            self::throw_exception(self::$error);
            return false;
        }
        if(self::$queryStr==''){
            self::throw_exception('没有执行SQL语句');
            return false;
        }
    }
    /**
     * 自定义错误处理
     * @param unknown $errMsg
     */
    public static function throw_exception($errMsg){
        echo '<div style="width:80%;background-color:#ABCDEF;color:black;font-size:20px;padding:20px 0px;">
                '.$errMsg.'
        </div>';
    }
    /**
     * 销毁连接对象，关闭数据库
     */
    public static function close(){
        self::$link=null;
    }
    public static function search($table1,$table2,$table3){
        $PdoMySQL=new PdoMySQL();
        $sql1="select * from ".$table1." where status='0'";
        $sql2="select * from ".$table2." where status='0'";
        $sql3="select * from ".$table3." where status='0'";
        $stmt1=$PdoMySQL->prepare($sql1);
        $stmt2=$PdoMySQL->prepare($sql2);
        $stmt3=$PdoMySQL->prepare($sql3);
        $stmt1->execute();
        $stmt2->execute();
        $stmt3->execute();
        //echo $username.'<hr/>'.$password;
        $row1=$stmt1->fetch();
        echo $row1[0];
    }
}
?>

原文：https://github.com/FantasticLBP/Company-Website-Pro/blob/master/model/PdoMySQL.class.php