SELECT*
FROM t_book
WHERE book_copy IN(5,6,7);
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635467401664.png)
SELECT*
FROM t_press
WHERE press_address LIKE'%北京%';
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635467517048.png)
SELECT*
FROM t_reader
WHERE reader_borrowtotal IS NULL LIMIT 2,4;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635467668854.png)
SELECT AVG (YEAR(CURDATE())-YEAR(reader_birthday)) AS 平均年龄,
MIN(YEAR(CURDATE())-YEAR(reader_birthday)) AS 最小年龄,
MAX(YEAR(CURDATE())-YEAR(reader_birthday))AS 最大年龄,
COUNT(reader_id) AS 读者人数
FROM t_reader;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635468969158.png)
作业题:
图片来源:嘉杰
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/527DD013-1853-4052-91B2-25FCE19017441635469946144.jpeg)
正确作业代码班上同学已经发在班级群里,我这个不一定正确,我主要分享这两张表✌️
/*SELECT *,borndate
FROM student
WHERE GradeId="1"
*/
SELECT *
FROM student
WHERE GradeId=1
ORDER BY borndate;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635469886303.png)
SELECT *
FROM result
WHERE SubjectNo=1
ORDER BY StudentResult DESC;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635470983663.png)
SELECT StudentNo,studentResult FROM result
WHERE ExamDate='2016-02-17'
ORDER BY studentresult DESC LIMIT 5;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635471895122.png)
SELECT COUNT(*),borndate FROM student GROUP BY YEAR(BORNDATE)
HAVING COUNT(*)>=2
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635472396107.png)
SELECT studentName,FLOOR(DATEDIFF(NOW(),bornDate)/365) FROM student
WHERE sex='女'
ORDER BY bornDate DESC LIMIT 1,7;
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635472469377.png)
SELECT MAX(studentresult),MIN(studentresult),MAX(studentresult)
FROM result WHERE
examDate='2016-02-17';
![](https://saas.bk-cdn.com/t/28fa19a1-bd4e-468d-b51a-cc1195795049/u/e41e744f-8a62-49c8-9e5b-0b3866856d0c/image1635472548143.png)
两张数据库表打包下载: