如何将多个json组合成一个？

[sigkl00181]

        $question = $_GET['question'];
        $arr = explode("|",$question);
        for($i = 0;$i <= 3; $i++){
            $rid = $arr[$i];
            $sql = "select * from xs_radio where rid = '$rid'";
            $result = mysql_query($sql);
    		$arr = array();
    		while($row = mysql_fetch_array($result, MYSQL_ASSOC)){
    			$ar[] = $row;  
    		}
    		$js = json_encode($ar);
            echo $js;
        }

这是查询的语句

[{"rid":"1","title":"\u6211\u662f\u8c01","a":"\u5b8b\u5411\u4e1c","b":"\u9b4f\u4eae","c":"\u738b\u514b\u5a07","d":"\u5b8b\u5b50\u6587","answer":"\u5b8b\u5411\u4e1c"}]
[{"rid":"2","title":"\u6211\u662f\u8c01","a":"\u9b4f\u4eae","b":"\u5218\u5fb7\u534e","c":"\u674e\u5a1c","d":"\u5f20\u626c","answer":"\u9b4f\u4eae"}]
[{"rid":"3","title":"\u6211\u662f\u8c01","a":"\u9b4f\u4eae","b":"\u738b\u514b\u5a07","c":"\u674e\u56fd\u4f1f","d":"\u738b\u83f2","answer":"\u738b\u514b\u5a07"}]
[{"rid":"16","title":"\u6211\u662f\u8c01","a":"\u5218\u5f66\u5bbe","b":"\u674e\u56fd\u632f","c":"\u7a0b\u79c0\u82b9","d":"\u738b\u514b\u5a07","answer":"\u738b\u514b\u5a07"}]

查询出来的结果。 如何把这三个json组合成一个？

[{"rid":"1","title":"\u6211\u662f\u8c01","a":"\u5b8b\u5411\u4e1c","b":"\u9b4f\u4eae","c":"\u738b\u514b\u5a07","d":"\u5b8b\u5b50\u6587","answer":"\u5b8b\u5411\u4e1c"},
{"rid":"2","title":"\u6211\u662f\u8c01","a":"\u9b4f\u4eae","b":"\u5218\u5fb7\u534e","c":"\u674e\u5a1c","d":"\u5f20\u626c","answer":"\u9b4f\u4eae"},
{"rid":"3","title":"\u6211\u662f\u8c01","a":"\u9b4f\u4eae","b":"\u738b\u514b\u5a07","c":"\u674e\u56fd\u4f1f","d":"\u738b\u83f2","answer":"\u738b\u514b\u5a07"},
{"rid":"16","title":"\u6211\u662f\u8c01","a":"\u5218\u5f66\u5bbe","b":"\u674e\u56fd\u632f","c":"\u7a0b\u79c0\u82b9","d":"\u738b\u514b\u5a07","answer":"\u738b\u514b\u5a07"}]

保存成这样的。

[wlei_coder]

转数组 然后合成一个数组 再转json

[xuzuning]

把 $ar[] = $row; 改为 $ar[$i][] = $row; 把 $js = json_encode($ar); echo $js; 移到 for 循环后面

[sigkl00181]

谢谢。