SELECT
l.limitId, l.limitName, l.limitURL, m.ModelName,o.OperateName
FROM limits l
LEFT JOIN model m ON m.ModelId=l.limitModelId
LEFT JOIN operate o ON o.OperateId=l.limitOperateNameId;
用戶表user:
user_id | user_name | user_sex |
100111 | 佳佳 | 女 |
課程表subject:
subject_id | subject_name | achievement | user_number |
111 | 計算機科學與技術 | 99 | 100111 |
學院表college:
college_id | college_name | subject_number |
201 | 網絡工程學院 | 111 |
select
u.user_id, u.user_name,u.user_sex,c.college_name,s.subject_name, s.achievement
from user u
LEFT JOIN subject s ON s.user_number=u. user_id
LEFT JOIN college c ON c.subject_number=s.subject_id;
三表關聯查詢結果:
user_id(學號) | user_name(姓名) | user_sex(性別) | college_name(學院) | subject_name(學科) | achievement(成績) |
100111 | 佳佳 | 女 | 網絡工程學院 | 計算機科學與技術 | 99 |