示例1：   

   $info = Db::table('client_good')->where("        id", 14380)->limit(3)->select();

SELECT * FROM `client_good` WHERE ( id ) LIMIT 3

    如果是下面这样就很危险

   $info = Db::table('client_good')->where("        id", 14380)->delete();

所以下面这个字符串很恐怖 ->where(" 

        推荐数组写

        //测试数组

        $where[" id  "] = 14380;

        $info = Db::table('client_good')->where($where)->limit(3)->select();

   ps：

       $info = Db::table('client_good')->where("id='$good_id'")->limit(3)->select();  这种存在sql注入问题，不过不考虑sql注入，范围问题比下面好。

       $info = Db::table('client_good')->where("        id", $good_id)->limit(3)->select();  //这种 会恒成立，危险性极大

        $where[" id  "] = 14380;

        $info = Db::table('client_good')->where($where)->limit(3)->select();   //最优方案 id会被trim

        $sql = "update client_good set click_num=click_num+1 where id=:g_id";   //原生的sql方案

        $flag = Db::execute($sql, ['g_id' => $g_id]);  //成功会输出1

        //下面的在thinkphp5就不行，在thinkphp8的thinkorm4.0 就没这个问题了。

        错误示例：查询表达式错误:0724323738b03a3209ba4ae5570b87f2

复杂sql非原生：

         

         $whereinit=[];

          $whereinit["clientkeynum"]=$clientkeynum;

            $p = $param['page'] ? $param['page'] : 1;

            $pagesize = $param['limit'];

            $offset = $pagesize * ($p - 1);

            //计算记录偏移量

            $card_number_id = isset($param['card_number_id']) ? $param['card_number_id'] : '';

            $card_number = isset($param['card_number']) ? $param['card_number'] : '';

            $user_name = isset($param['user_name']) ? $param['user_name'] : '';

            $oper_text = isset($param['oper_text']) ? $param['oper_text'] : '';

            $where = "1 = 1  and  clientkeynum=:clientkeynum ";

            $wherebind = [];

            $wherebind["clientkeynum"] = $clientkeynum;

            $between_time = isset($param['between_time']) ? $param['between_time'] : '';

            //如果下单日期不为空则

            if ($between_time != '') {

                $between_time_arr = explode('~', $between_time);

                $start_time = $between_time_arr[0];

                $end_time = $between_time_arr[1];

                $where .= " and create_time  >=:start_time  and  create_time <= :end_time ";

                $wherebind["start_time"] = $start_time;

                $wherebind["end_time"] = $end_time;

            }

            if ($card_number_id != '') {

                $where .= "and  card_number_id  = :card_number_id ";

                $wherebind["card_number_id"] = $card_number_id;

            }

            if ($card_number != '') {

                $where .= "and  card_number  = :card_number ";

                $wherebind["card_number"] = $card_number;

            }

            if ($user_name != '') {

                $where .= "and  user_name  = :user_name ";

                $wherebind["user_name"] = $user_name;

            }

            if ($oper_text != '') {

                $where .= " and  `oper_text`  like  :oper_text ";

                $wherebind["oper_text"] = "%{$oper_text}%"; // 绑定值添加%，实现模糊匹配

            }

            //默认按照时间降序

            $count = Db::table('card_log')->where($whereinit)->where($where,$wherebind)->count();

            $list = Db::table('card_log')->where($whereinit)->where($where,$wherebind)->order('log_id', 'desc')->limit($offset . ',' . $pagesize)->select();

        $keynum 

= "AE287311FA9EEC0D49D1F6F61486A35F";

        $name = "1xDQMzK7ur0P+gq9iHrhGCrfF4oIp/yR";

        $clientkeynum = "0724323738B03A3209BA4AE5570B87F2";

        $basekeynum = "CDEFF2D05CAA06DA2416A4BA6740FB2F";

        $account_info = Db::table('client_merchant_member')->where("keynum","<>",$keynum)->where("name", $name)->where("clientkeynum", $clientkeynum)->where("merchantkeynum", $basekeynum)->select();

        print_r($account_info);

        echo  Db::table('client_merchant_member')->getLastSql();

        die;

       在thinkphp5.0种使用wherein的时候phone 既可以是数组也可也是逗号拼接的字符串

        //$phone[]= 17631253743;

        //$phone[]= 18833253743;

        $phone = "17631253743,18833253743";

        $list = Db::table('plat_sms_code')->wherein("phone", $phone)->order("id", "desc")->limit(2)->select();

        echo Db::table('plat_sms_code')->getLastSql();

        print_r($list);

        die;