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如何连接 MySQL 中的字段？

2023-06-20 10:05:03 401

要连接MySQL中的字段，您可以GROUP_CONCAT()与GROUPBY一起使用。让我们首先创建一个表-

mysql> create table DemoTable
   (
   StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   StudentName varchar(30),
   StudentScore int
   );

使用插入命令在表中插入记录-

mysql> insert into DemoTable( StudentName,StudentScore) values('Bob',80);
mysql> insert into DemoTable( StudentName,StudentScore) values('Bob',80);
mysql> insert into DemoTable( StudentName,StudentScore) values('Chris',90);
mysql> insert into DemoTable( StudentName,StudentScore) values('Chris',70);
mysql> insert into DemoTable( StudentName,StudentScore) values('Bob',50);
mysql> insert into DemoTable( StudentName,StudentScore) values('David',60);
mysql> insert into DemoTable( StudentName,StudentScore) values('Chris',99);
mysql> insert into DemoTable( StudentName,StudentScore) values('David',88);

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-

+-----------+-------------+--------------+
| StudentId | StudentName | StudentScore |
+-----------+-------------+--------------+
| 1         | Bob         | 80           |
| 2         | Bob         | 80           |
| 3         | Chris       | 90           |
| 4         | Chris       | 70           |
| 5         | Bob         | 50           |
| 6         | David       | 60           |
| 7         | Chris       | 99           |
| 8         | David       | 88           |
+-----------+-------------+--------------+
8 rows in set (0.00 sec)

以下是连接MySQL中的字段的查询-

mysql> select
StudentName, group_concat(StudentScore separator ',') as Score
from DemoTable
group by StudentName;

这将产生以下输出-

+-------------+----------+
| StudentName | Score    |
+-------------+----------+
| Bob         | 80,80,50 |
| Chris       | 90,70,99 |
| David       | 60,88    |
+-------------+----------+
3 rows in set (0.24 sec)

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如何连接 MySQL 中的字段？

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