闭包查询
tbmember表闭包查询查询 openid=‘abc并且islose=0并且islogout=0并且（wx_unionid=null或者wx_unionid=’'）

Db::table('tbmember')->where(['openid'=>'abc','islose'=>0,'islogout'=>0])->where(function ($query){$query->where('wx_unionid',null)->whereOr('wx_unionid','');})->select();