写了一个PHP版本的MONGODB语法解析器，可以通过类似SQL的语法来进行查询，不知道有人需要不，分享一下吧

$query = new MongoQueryParser();
$query->query("a=0");
$queryRst = $query->result;

$query = new MongoQueryParser();
$query->query("a=0 && b > 2");
$queryRst = $query->result;

$query = new MongoQueryParser();
$query->query("(a=0 && b > 2) || c <= 5");
$queryRst = $query->result;

<?php
class MongoQueryParser {
	function __construct() {
		$this->result =[];
	}
	
	public $result;
	
	public $leftFirstReg = "/\(([^\s]+)\)(&&|\|\|)([^\s]+$)/";//匹配左括号优先
	public $rightFirstReg = "/([^\s]+?)(&&|\|\|)\(([^\s]+)\)$/";//右括号优先
	public $allReg = "/\(([^\s]+)\)(&&|\|\|)\(([^\s]+)\)$/";//左右括号模式
	public $reg1 = "/([^\s]+)(&&|\|\|)([^\s]+)/";
	public $reg2 = "/([\w]+)([=<>]+)([^\s]+)/";
	public $opMap = [">"=>'$gt',"<"=>'$lt',">="=>'$gte',"<="=>'$lte'];
	private $meetOr = false;
	
	/**
	 * 将自定义的查询语句转换成MONGODB的查询语句
	 * 例1：a=3
	 * 例2：a>0&&a<2
	 * 例3：a>0&&a<2||c>3
	 */
	function query($query){
		$query =preg_replace("/s/","",$query);
		$this->result = $this->exec($query,false,false);
		return $this->result;
	}
		
	function exec($query,$layer,$fromAnd){
		if(preg_match($this->allReg, $query,$matches1) > 0 || 
			preg_match($this->rightFirstReg, $query,$matches2) > 0 ||
			preg_match($this->leftFirstReg, $query,$matches3) > 0 || 
			preg_match($this->reg1, $query,$matches4)){
			$mat = null;
			$leftSame = false;
			$rightSame = false;
			if(count($matches1) > 0){
				$mat = $matches1;
			}else if(count($matches2) > 0){
				$leftSame = true;
				$rightSame = false;
				$mat = $matches2;
			}else if(count($matches3) > 0){
				$leftSame = false;
				$rightSame = true;
				$mat = $matches3;
			}else if(count($matches4) > 0){
				$leftSame = true;
				$rightSame = true;
				$mat = $matches4;
			}
			
			$op = $mat[2];
			$left = $mat[1];
			$right = $mat[3];
			
			if($op == "&&"){//如果操作符是AND
				$rst = null;
				if(!$layer || !$fromAnd){//如果不同层，或者调用来自上一层的or，那么就建立一个$and操作符
					$rst['$and'] = [];
					$larr = $this->exec($mat[1],$leftSame,true);
					$rarr = $this->exec($mat[3],$rightSame,true);
					$rst['$and'] = $this->mergeArr($rst['$and'],$larr, $rarr);
					return $rst;
				}else{//如果同层，直接把值都放到同层数组去
					$rst = array_merge($this->exec($mat[1],$leftSame,true),$this->exec($mat[3],$rightSame,true));
					return $rst;
				}
			}else if($op == "||"){
				if(!$layer || $fromAnd){//如果不同层
					$rst['$or'] = [];
					$larr = $this->exec($mat[1],$leftSame,false);
					$rarr = $this->exec($mat[3],$rightSame,false);
					$rst['$or'] = $this->mergeArr($rst['$or'],$larr, $rarr);
				}else{
					$rst = [];
					$rst = array_merge($this->exec($mat[1],$leftSame,false),$this->exec($mat[3],$rightSame,false));
				}
				return $rst;
			}
		}
		else{//如果最终已经分解成a=b的形式时，就在此解析
			preg_match($this->reg2, $query,$matches);
			if(count($matches) >= 4){
				$left = $matches[1];
				$op = $matches[2];
				$right = $matches[3];
				$rst = [];
				if($op == "="){
					if(is_numeric($right)){
						$rst[$left] = (float)$right;
					}else{
						$rst[$left] = $right;
					}
				}else{
					if(!isset($rst[$left])){
						$rst[$left] = [];
					}
					if(is_numeric($right)){
						$rst[$left][$this->opMap[$op]] = (float)$right;
					}else{
						$rst[$left][$this->opMap[$op]] = $right;
					}
				}
				return $rst;
			}
		}
	}
	
	function mergeArr($rst,$larr,$rarr){
		foreach ($larr as $lk=>$lv){
			$lcond = [];
			$lcond[$lk] = $lv;
			$rst[] = $lcond;
		}
			
		foreach ($rarr as $rk=>$rv){
			$rcond = [];
			$rcond[$rk] = $rv;
			$rst[] = $rcond;
		}
		return $rst;
	}
}

?>