用pdo连接两个表

问题描述

我想在数据库中联接两个表。它的“经典”方式效果很好，但是我的脚本中有很多选择查询，所以我想简化一下...

这是联合sql：

SELECT
    matches.id,matches.start_time,matches.category_id,matches.highl,first_team.tid,first_team.t_name,second_team.tid,second_team.t_name AS ft_name 
FROM matches 
    INNER JOIN teams AS first_team ON matches.first_team_id = first_team.tid 
    INNER JOIN teams AS second_team ON matches.second_team_id = second_team.tid 
ORDER BY matches.id DESC 
    LIMIT 10

我想要达到的目标是这样的，但是我不完全知道如何添加上面复制的所有值。

public function getMatches($table,$conditions = array()){
    $sql = 'SELECT ';
    $sql .= array_key_exists("select",$conditions)?$conditions['select']:'';
    $sql .= ' FROM '.$table;
    if(array_key_exists("where",$conditions)){
        $sql .= ' WHERE ';
        $i = 0;
        foreach($conditions['where'] as $key => $value){
            $pre = ($i > 0)?' AND ':'';
            $sql .= $pre.$key." = '".$value."'";
            $i++;
        }
    }

    if(array_key_exists("inner_join",$conditions)){
        $sql .= ' INNER JOIN '.$conditions['inner_join'];
    }

    if(array_key_exists("on",$conditions)){
        $sql .= ' ON '.$conditions['on'];
    }

    if(array_key_exists("as",$conditions)){
        $sql .= ' AS '.$conditions['as'];
    }

    if(array_key_exists("order_by",$conditions)){
        $sql .= ' ORDER BY '.$conditions['order_by'];
    }

    if(array_key_exists("start",$conditions) && array_key_exists("limit",$conditions)){
        $sql .= ' LIMIT '.$conditions['start'].','.$conditions['limit'];
    }elseif(!array_key_exists("start",$conditions)){
        $sql .= ' LIMIT '.$conditions['limit'];
    }

    $query = $this->db->prepare($sql);
    $query->execute();

    if(array_key_exists("return_type",$conditions) && $conditions['return_type'] != 'all'){
        switch($conditions['return_type']){
            case 'count':
                $data = $query->rowCount();
            break;
            case 'single':
                $data = $query->fetch(PDO::FETCH_ASSOC);
            break;
            default:
                $data = '';
        }
    }else{
        if($query->rowCount() > 0){
            $data = $query->fetchAll();
        }
    }
    return !empty($data)?$data:false;
    }
}

以下是输出：

<div class="panel-heading">Matches</div>
    <table class="table">
        <tr>
          <th>#</th>
          <th>First Team</th>
          <th>Second Team</th>
          <th>Start Time</th>
        </tr>
        <?PHP
        include 'inc/functions.PHP';
        $db = new DB();
        $matches = $db->getMatches('matches',array('inner_join'=>'teams'),array('as'=>'first_team'),array('on'=>'matches.first_team_id = first_team.tid'),array('as'=>'second_team'),array('on'=>'matches.second_team_id = second_team.tid'),array('order_by'=>'matches.id'));
        if(!empty($matches)){ $count = 0; foreach($matches as $result){ $count++;?>
        <tr>
          <td><?PHP echo $count; ?></td>
          <td><?PHP echo $result['ft_name']; ?></td>
          <td><?PHP echo $result['t_name']; ?></td>
          <td><?PHP echo $result['start_time']; ?></td>
        </tr>
        <?PHP } }else{ ?>
        <tr><td colspan="4">No entry found!</td>
        <?PHP } ?>
    </table>
</div>

解决方法

老实说，对于我的一生，我永远都不会明白，PHP数组的墙是如何

array('inner_join'=>'teams'),array('as'=>'first_team'),array('on'=>'matches.first_team_id = first_team.tid'),array('inner_join'=>'teams'),array('as'=>'second_team'),array('on'=>'matches.second_team_id = second_team.tid'),array('order_by'=>'matches.id'));

甚至可以被认为比优雅紧凑的SQL“更短”

SELECT
    matches.id,matches.start_time,matches.category_id,matches.highl,first_team.tid,first_team.t_name,second_team.tid,second_team.t_name AS ft_name 
FROM matches 
    INNER JOIN teams AS first_team ON matches.first_team_id = first_team.tid 
    INNER JOIN teams AS second_team ON matches.second_team_id = second_team.tid 
ORDER BY matches.id DESC 
    LIMIT 10

更不用说意义和可读性了。

您是要节省自己输入一些SELECT或FROM这样的SQL关键字吗？认真吗用有意义且易于理解的SQL弄得一团糟真的值得吗？

join mysql