mysql 查询 - 个人记录

1.mysql 子查询使用父查询字段作为条件，查询B表数量

$unit = "公司";
$department = "部门";
Db::query("select a.ep_id,a.ep_topRoleId,
         (select count(us_id) from tb_user as b where find_in_set(b.us_roleid, a.ep_topRoleId) and us_unit='{$unit}' and us_department='{$department}') as num 
         from tb_exam_paper as a");

2.mysql 根据某字段排行，获取当前用户排名

Db::query("SELECT * FROM
          (SELECT ui_uid,ui_integral,ui_time,(@rank:=@rank+1) AS us_rank FROM tb_user_integral_current, (SELECT (@rank:=0)) b 
          WHERE {$where} ORDER BY ui_integral DESC,ui_uid Asc) c WHERE ui_uid={$uid}");