php实现多表（四表）连接

<?php 

include_once "DBHelper.php";
define('HOST', '127.0.0.1');
define('USER', 'root');
define('PASSWORD', '');
define('DBNAME', 'sxbcms');

/*define('HOST', '120.25.144.215');
define('USER', 'root');
define('PASSWORD', '88ac86754a');
define('DBNAME', 'sxbcms');*/

class student extends DBHelper{

    function __construct()
    {
        parent::__construct();
    }

public function students(){
     $sql = "select user.id , user.mobile ,name, sex, user.birthday ,area, user.email, `fgraduate` from  hr_users user left join hr_student on user.id = hr_student.user_id where user.usertype =1 ";
     $ret = $this->find($sql);
    return $ret;
 }

//获取最高的学位 limit 1
public function edu($user_id){
    $sql = "select `user_id`, `fdegree`, `grade` , `fschool` , `fmajor`  from hr_student_eduexp where user_id = $user_id order by fdegree desc limit 1";
    //echo $sql;
    $ret = $this->find($sql);
    return $ret;
}

public function citys(&$data){
    $sql ="select * from hr_city ";
    $ret = $this->find($sql);
    $temp = [] ;
    foreach ($ret as $key => $value) {
        $temp[$value['id']] = $value['cityname'];
    }
    foreach($data as $key=>$value){
        $city = $value['area'];//获取area 的id
        if(isset($temp[$city]))
        {
            $data[$key]['citys']=$temp[$city];
            unset($data[$key]['city']);
        }
    }
}

public function csv($file,$list)
    {
        $fh = fopen($file,'w') or die("Can't open file.csv");

        foreach ($list as $sales_line) {
          if (fputcsv($fh, $sales_line) === false) {
            die("Can't write CSV line");
          }
        }
        fclose($fh) or die("Can't close file.csv");

    }
}

$stu = new student();
$listStu = $stu->students();
foreach ($listStu as $key => $value) {
    $user_id = $value['id'];//获取用户的id
    if(!empty($user_id)){
        $eduStu = $stu->edu($user_id);
        /*echo "<pre>";print_r($eduStu);echo "</pre>";*/
        //根据user_id遍历教育经历,过滤掉为空的教育经历
        if(is_array($eduStu)){
            foreach ($eduStu as $edu) {
              $listStu[$key]['fdegree'] = $edu['fdegree'];
              $listStu[$key]['grade'] = $edu['grade'];
              $listStu[$key]['fschool'] = $edu['fschool'];
              $listStu[$key]['fmajor'] = $edu['fmajor'];
            }
        }
    }
}

$stu->citys($listStu);
$stu->csv("student123.csv", $listStu);

?>

DBhelper.php

<?php
header("Content-type:text/html;charset=utf-8");

class DBHelper{

    protected $conn;

    function __construct()
    {

        $this->InitConn();

    }

    private function InitConn()
    {

        $this->conn = new mysqli(HOST, USER, PASSWORD, DBNAME);

        if ($this->conn->connect_errno) {

            printf("Connect failed: %s\n", $this->conn->connect_error);

            exit();

        }

        $this->conn->query("set names utf8");

    }

    public function changeDb($user, $pass, $ip, $db)
    {

        $this->conn = new mysqli($ip, $user, $pass, $db);

        if ($this->conn->connect_errno) {

            printf("Connect failed: %s\n", $this->conn->connect_error);

            exit();

        }

        $this->conn->query("set names utf8");

    }

    public function Execute($sql)
    {
        echo $sql."\n\n";
        return $this->conn->query($sql);

    }

    public function find($sql)
    {

        $ret = [];

        $list = $this->conn->query($sql);

        while ($row = $list->fetch_array(MYSQLI_ASSOC)) {

            $ret[] = $row;

        }

        return $ret;

    }

    public function findOne($sql)
    {

        $list = $this->conn->query($sql);

        $row = $list->fetch_array(MYSQLI_ASSOC);

        return $row;

    }

    public function Save($table ,$data)
    {
        $sql ="insert into $table set ";
        foreach ($data as $key => $value) {
            $data[$key] = addslashes($value);
        }
        foreach ($data as $key => $value) {
            $sql =$sql ."`".$key."`='". $value ."',";
        }
        $sql = substr($sql,,count($sql)-);
        echo $sql."\n";
        return $this->conn->query($sql);
    }

    public function Close()
    {

        $this->conn->close();

    }

    public function executesql($sql)
    {
        return $this->conn->query($sql);
    }

}

举例子

<?php

include_once "DBHelper.php";
define('HOST', '120.25.144.215');
define('USER', 'root');
define('PASSWORD', '88ac86754a');
define('DBNAME', 'sxbcms');

/*
自己注册企业列表

*/

/**
*
*/
class enterprise  extends DBHelper
{

    function __construct()
    {
        parent::__construct();
    }

    public function listEnt()
    {
        $sql = "select hr_company.id , comfullname ,email ,mobile ,scale ,industry,mainproduct,enterprise ,hr_users.id as  user_id from hr_company  left join hr_users on hr_company.user_id = hr_users.id
            where  user_id not in (select user_id from hr_edit_create_company)";

        $ret = $this->find($sql);
        return $ret;
    }

    /*
    发不过的职位总数

    */

    public function jobs()
    {
        $sql ="select count(*) as ct  ,user_id from hr_job where     addtime > '2016-01-01' and  addtime < '2016-09-30'     group by user_id" ;
        $ret = $this->find($sql);
        $temp =[];
        foreach ($ret as $key => $value) {
            $uid = $value['user_id'];
            $temp[$uid] = $value['ct'];
        }

        return $temp;

    }

    public function citys(&$data)
    {
        $sql ="select * from hr_city ";
        $ret = $this->find($sql);
        $temp = [] ;
        foreach ($ret as $key => $value) {
            $temp[$value['id']] = $value['cityname'];
        }
        foreach($data as $key=>$value){

            $provinces = $value['provinces'];
            $city = $value['city'];
            if(isset($temp[$provinces]))
            {
                $data[$key]['pro']=$temp[$provinces];
                $data[$key]['citys']=$temp[$city];
                unset($data[$key]['provinces']);
                unset($data[$key]['city']);
            }

        }

    }

    //设置行业
    public function injertindustry(&$data)
    {
        $sql ="select * from hr_industry";
        $ret = $this->find($sql);
        $temp = [] ;
        foreach ($ret as $key => $value) {
            $temp[$value['id']] = $value['name'];
        }
        foreach ($data as $key => $value) {
            $industry =$value['industry'];

            if(isset($temp[$industry])){
                $name  =$temp[$industry];
            $data[$key]['industry_name'] = $name;
            }else
            {
                $data[$key]['industry_name'] ="";

            }
        }
    }

    public function Position(&$data)
    {
        $sql ="select * from hr_position";
        $ret = $this->find($sql);
        $temp = [] ;
        foreach ($ret as $key => $value) {
            $temp[$value['id']] = $value['name'];
        }
        foreach ($data as $key => $value) {
            $jobtype =$value['jobtype'];

            if(isset($temp[$jobtype])){
                $name  =$temp[$jobtype];
            $data[$key]['jobtype'] = $name;
            }else
            {
                $data[$key]['jobtype'] ="";

            }
        }

    }

    /*
    职位的投递量
    */
    public function listJobBYCompany()
    {
        //获取全部的job-id和对应的company
        $sql = "select user_id ,id from hr_job";
        $ret = $this->find($sql);    

        $sql = "select count(*) , jobid  from  hr_action  group by  jobid ";
        $list = $this->find($sql);    

        $temp =[];
        foreach ($list as $key => $value) {
            $jobid =$value['jobid'];
            $temp[$jobid] =$value;
        }

        foreach ($ret as $key => $value) {
            $jobid =$value['id'];
            $ret[$key]['total'] =$temp[$jobid];
        }

        return $temp;

    }

    public function listContainJob($user_id,$email=null ,$name=null)
    {
            $sql = "select  id , title,num ,addtime  ,provinces ,city,jobtype ,viewnum   from hr_job where user_id=".$user_id;
            $list = $this->find($sql);
            foreach ($list as $key => $value) {
                $jobid =$value["id"];
                $sql = "select count(*)  as ct from   hr_action where  jobid=".$jobid;
                $ct = $this->findOne($sql);
                $list[$key]['deliver'] = $ct['ct'];
                $list[$key]['email'] = $email;
                $list[$key]['name'] = $name;
                $sql = "select count(*)  as ct from   hr_action where  jobid=".$jobid ." and  open_viwe = 1";
                $ct = $this->findOne($sql);
                $list[$key]['resumeviewn'] =    $ct['ct'];
            }
            return $list;
    }

    public function csv($file,$list)
    {
        $fh = fopen($file,'w') or die("Can't open file.csv");

        foreach ($list as $sales_line) {
          if (fputcsv($fh, $sales_line) === false) {
            die("Can't write CSV line");
          }
        }
        fclose($fh) or die("Can't close file.csv");

    }

}

$ent= new  enterprise();
$list = $ent->listEnt();
$jobs =$ent->jobs();
foreach ($list as $key => $value) {
    $uid = $value['user_id'];
    if(isset($jobs[$uid])){
        $list[$key]['total'] = $jobs[$uid];
    }else
    {
        $list[$key]['total'] =  ;
    }

}
$ent->injertindustry($list);
$jobs =[];
foreach ($list as $key => $value) {
    $uid = $value['user_id'];
    if(intval($uid)>){
        $email =$value['email'];
        $name =$value['comfullname'];
    $li =    $ent->listContainJob($uid,$email ,$name);
    if(!empty($li))
    {
        foreach($li as $item)
        {
            array_push($jobs, $item);
        }
    }
    }

}

$ent->citys($jobs);
$ent->Position($jobs);
$ent->csv("ent.csv", $list);
$ent->csv("jobs.csv", $jobs);