sql语句（逐渐添加中）

//向数据库里插入字段内容，$_G['uid']是当前页面session中uid的值

DB::query("INSERT INTO mk_tizhong (height,weight,addtime,sex,BMI,legendweight,nowstat,uid)

VALUES ('$height', '$weight', '$addtime', '$sex', '$BMI', '$legendweight','$nowstat',".$_G['uid'].");");

//选取某一天的systolic_pressure字段的平均值。

DB::query("select avg(systolic_pressure) as systolic,avg(diastolic_pressure) as diastolic from mk_xueya where u.date(Ym).$day);