php - 创建mysql select - 多个参数(有些是不必要的)

Question

假设我在 PHP 中有以下对象:

class param{
 public $home; //set by another function
 public $user; //set by another function
 public function createRequest(){
//in this function I want to create mysql string with $home and $user
  $sql = "select * FROM table WHERE home =".$this->home." AND user=".$this->user;
  return $sql;
}

问题是，$home(或$user)可能是空字符串，在这种情况下，我想包括所有家庭(或用户)，而不仅仅是列，其中home =“”(或user =“”)；

您有什么建议吗？或者这个想法是错误的？ (我只是 PHP 的初学者)

Answer 1

这不是最优雅的，我们应该使用 PDO 准备好的语句......但为了举例:

class param{
  public $home; //set by another function
  public $user; //set by another function
  public function createRequest(){
    //in this function I want to create mysql string with $home and $user
    $sql = "select * FROM table";
    if(strlen($this->home) || strlen($this->user)) {
      $sql .= " WHERE ";
      $and = array();
      if(strlen($this->home))
        $and[] = " home='".$this->home."' ";
      if(strlen($this->user))
        $and[] = " user='".$this->user."' "; 
      $sql .= implode(" AND ", $and);
    }
    return $sql;
  }
}

测试输出示例:

$p = new param;
echo $p->createRequest();
echo "<br>";

$p->home = "foo";
echo $p->createRequest();
echo "<br>";

$p->user = "bar";
echo $p->createRequest();
echo "<br>";

$p->home = "";
echo $p->createRequest();

将产生:

select * FROM table
select * FROM table WHERE home='foo' 
select * FROM table WHERE home='foo' AND user='bar' 
select * FROM table WHERE user='bar'