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在MySQL中求和对应的重复记录

2024-04-29 23:31:04 357

让我们首先创建一个表-

mysql> create table DemoTable
   -> (
   -> StudentName varchar(20),
   -> StudentMarks int
   -> );

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable values('Chris',50);
mysql> insert into DemoTable values('David',70);
mysql> insert into DemoTable values('Chris',80);
mysql> insert into DemoTable values('David',90);

使用select语句显示表中的所有记录-

mysql> select * from DemoTable;

这将产生以下输出-

+-------------+--------------+
| StudentName | StudentMarks |
+-------------+--------------+
| Chris       |           50 |
| David       |           70 |
| Chris       |           80 |
| David       |           90 |
+-------------+--------------+
4 rows in set (0.00 sec)

这是对相应重复记录进行求和的查询，即学生的分数-

mysql> select StudentName,sum(StudentMarks) from DemoTable group by StudentName;

这将产生以下输出-

+-------------+-------------------+
| StudentName | sum(StudentMarks) |
+-------------+-------------------+
| Chris       |               130 |
| David       |               160 |
+-------------+-------------------+
2 rows in set (0.00 sec)

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在MySQL中求和对应的重复记录

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