一、子查询(查询选秀3-245课程的成绩高于103号同学该门课程成绩的所有同学的记录)
mysql> select degree from score where sno = '103' and cno = '3-245';--先找到该成绩的值!!
+--------+
| degree |
+--------+
| 89 |
+--------+
1 row in set (0.00 sec)
mysql> select * from score
-> where cno='3-105'
-> and
-> degree > (select degree from score where sno = '103' and cno = '3-245');
+-----+-------+--------+
| sno | cno | degree |
+-----+-------+--------+
| 100 | 3-105 | 100 |
| 103 | 3-105 | 99 |
+-----+-------+--------+
2 rows in set (0.03 sec)
二、子查询(查询高于103号同学的3-245课程成绩的所有同学的成绩记录)
mysql> select * from score
-> where degree > (select degree from score where sno = '103' and cno = '3-245');
+-----+-------+--------+
| sno | cno | degree |
+-----+-------+--------+
| 100 | 3-105 | 100 |
| 102 | 3-245 | 100 |
| 103 | 3-105 | 99 |
| 104 | 3-245 | 98 |
+-----+-------+--------+
4 rows in set (0.00 sec)
三、子查询(year函数和in关键字)
查询和100、105这两位同学的出生年份相同的所有学生!
mysql> select * from student;
+-----+--------+---------------------+-------+-------+
| sno | sname | sbirthday | class | ssex |
+-----+--------+---------------------+-------+-------+
| 100 | Java | 1977-09-01 00:00:00 | 95033 | man |
| 101 | C | 1975-08-21 00:00:00 | 95034 | woman |
| 102 | C++ | 1976-02-11 00:00:00 | 95035 | woman |
| 103 | C# | 1974-12-01 00:00:00 | 95034 | woman |
| 104 | Python | 1977-10-11 00:00:00 | 95033 | man |
| 105 | JS | 1974-11-11 00:00:00 | 95033 | woman |
+-----+--------+---------------------+-------+-------+
6 rows in set (0.09 sec)
mysql> select * from student where sno in (100,105);
+-----+-------+---------------------+-------+-------+
| sno | sname | sbirthday | class | ssex |
+-----+-------+---------------------+-------+-------+
| 100 | Java | 1977-09-01 00:00:00 | 95033 | man |
| 105 | JS | 1974-11-11 00:00:00 | 95033 | woman |
+-----+-------+---------------------+-------+-------+
2 rows in set (0.04 sec)
mysql> select year(sbirthday) from student where sno in (100,105);
+-----------------+
| year(sbirthday) |
+-----------------+
| 1977 |
| 1974 |
+-----------------+
2 rows in set (0.08 sec)
mysql> select * from student
-> where year(sbirthday) in (select year(sbirthday) from student where sno in (100,105));
+-----+--------+---------------------+-------+-------+
| sno | sname | sbirthday | class | ssex |
+-----+--------+---------------------+-------+-------+
| 100 | Java | 1977-09-01 00:00:00 | 95033 | man |
| 103 | C# | 1974-12-01 00:00:00 | 95034 | woman |
| 104 | Python | 1977-10-11 00:00:00 | 95033 | man |
| 105 | JS | 1974-11-11 00:00:00 | 95033 | woman |
+-----+--------+---------------------+-------+-------+
4 rows in set (0.10 sec)
SQL语句高级(三)——子查询
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转载自blog.csdn.net/qq_37150711/article/details/87223927
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