Question

这是我的问题。我在Oracle数据库上有4个表：

团队（teamID，teamName）
TeamMembers（membersID，teamID，membersStatusID）
成员（membersID，membersName）
状态（membersStatusID，statusName）

我需要获取teamName，这些团队中teamMembers的数量以及状态为“队长”的成员的姓名......所有这些都在一个{{1}中在SQL中。

这个问题很长时间没有解决方案......任何想法？

编辑：我需要查看所有团队，即使其中没有成员。

Answer 1

我的oracle上有点生疏，所以这里可能会有一些轻微的语法问题，但我会试一试：

SELECT t.teamName,
  count(*) AS teamMembers,
  c.membersName as teamCaptain
FROM team t
  INNER JOIN TeamMembers tm ON tm.teamID = t.teamID
  LEFT JOIN Members m ON m.membersID = tm.membersID
  LEFT JOIN TeamMembers tmc ON tmc.teamID = t.teamID AND tmc.memberStatusID = "Captain"
  LEFT JOIN Members c ON c.membersID = tmc.membersID
  GROUP BY t.teamName, c.membersName

编辑：忘记GROUP BY行！

Answer 2

select t.team_id, t.teamName, count(tm.teamid), m.membersname
from team t, teammembers tm, members m, status s
where t.teamid = tm.teamid (+)
and tm.membersid = m.membersid (+)
and m.membersstatusid = s.statusid (+)
and s.statusname = 'Captain'
group by t.team_id, t.teamName, m.membersname

Answer 3

SELECT
teamName,
b.[Number Of Members],
c.membersName AS [Captian]
FROM
Team
LEFT JOIN
(
SELECT
    COUNT(*) AS [Number Of Members],
    teamID
FROM
    TeamMembers
GROUP BY
    teamID
) AS b ON Team.teamID = c.teamID
LEFT JOIN
(
SELECT
    membersName,
    teamID
FROM
    Members
INNER JOIN
    TeamMembers ON Members.membersID = TeamMembers.membersID
INNER JOIN
    Status ON TeamMembers.memberStatusID = Status.memberStatusID AND Status.statusName = 'Captian'
) AS c ON c.teamID = Team.teamID

可以工作。可能需要调整它，因为b select语句中的group by。我也只是在sql中写这个，因为我不知道oracle语法

Answer 4

我现在无法测试此选择，但你可以试试这个：

select team.teamName,count(distinct members.membersID) numMembers,
MAX(CASE when status.statusName='CAPTAIN' then members.membersname else null END) Captain
from team,teammembers,members,status 
where team.teamID=teammembers.teamID(+)
and teammembers.membersID=members.membersID(+)
and teamMembers.memberStatusID=status.memberstatusID(+)
group by team.teamName;

SQL请求：如何使用多表和calcul进行特定选择？

4 个答案: