Question

上面是我的查询...但是observer_ID和staff_ID的相应名称在另一个名为staff的表中。所以我需要加入（o.observer_ID = s.staff_ID）AND（o.staff_ID = s.staff_ID）以获取观察者和被观察者的两个名称（o.staff_ID）。请帮帮我。感谢

SELECT DISTINCT o.Room, o.Date,o.Module_code,o.observer_ID,o.staff_ID,o.form_id
FROM mbm2_db.observation_details as o,mbm2_db.Staff as s
WHERE o.date = '2011-08-09' and o.Module_code = 'IS5103'

Answer 1

SELECT DISTINCT 
    o.Room, o.Date,o.Module_code,o.observer_ID,o.staff_ID,o.form_id,
    s1.name, s2.name
FROM 
    mbm2_db.observation_details AS o
    LEFT JOIN mbm2_db.Staff AS s1 ON o.observer_ID = s1.staff_ID
    LEFT JOIN mbm2_db.Staff AS s2 ON o.staff_ID = s2.staff_ID
WHERE 
    o.date = '2011-08-09' AND o.Module_code = 'IS5103'

Answer 2

也许是一个自我内心的联系：

SELECT DISTINCT o.Room, o.Date,o.Module_code, o.observer_ID, o.staff_ID, o.form_id 
FROM mbm2_db.observation_details As o
JOIN mbm2_db.Staff As s ON o.staff_ID = s.staff_ID
JOIN mbm2_db.Staff As b ON b.observer_ID = s.staff_ID
WHERE o.date = '2011-08-09' and o.Module_code = 'IS5103';

Answer 3

 SELECT DISTINCT o.Room, o.Date,o.Module_code,o.observer_ID,o.staff_ID,o.form_id 
 FROM mbm2_db.observation_details o, mbm2_db.Staff s 
 WHERE o.date = '2011-08-09' 
  AND o.Module_code = 'IS5103' 
  AND o.staff_ID=s.staff_ID 
  AND o.observer_ID=s.staff_ID

Answer 4

SELECT DISTINCT o.Room, o.Date, o.Module_code, o.observer_ID, o.staff_ID, o.form_id 
FROM (mbm2_db.observation_details AS o LEFT JOIN mbm2_db.Staff AS observer ON o.observer_ID = oberver.staff_ID)
    LEFT JOIN mbm2_db.Staff AS observed ON o.staff_ID = observed.staff_ID
WHERE o.date = '2011-08-09' and o.Module_code = 'IS5103'

告诉我它是否有效（并手动检查一些值）。

加入MYSQL查询问题

4 个答案: