新行分隔符在MySQL的group_concat函数中不起作用？如何正确使用它？

要在group_concat（）函数中使用新行分隔符，请按照以下语法 –

select group_concat(concat_ws(' ',yourColumnName1, yourColumnName2) SEPARATOR "\r  
") from yourTableName;

让我们首先创建一个表 –

mysql> create table DemoTable
   (
   Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   FirstName varchar(20),
   LastName varchar(20)
   );
Query OK, 0 rows affected (0.67 sec)

使用insert命令在表中插入一些记录 –

mysql> insert into DemoTable(FirstName,LastName) values('John','Smith');
Query OK, 1 row affected (0.10 sec)

mysql> insert into DemoTable(FirstName,LastName) values('David','Miller');
Query OK, 1 row affected (0.14 sec)

mysql> insert into DemoTable(FirstName,LastName) values('John','Doe');
Query OK, 1 row affected (0.13 sec)

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 –

+----+-----------+----------+
| Id | FirstName | LastName |
+----+-----------+----------+
| 1  | John      | Smith    |
| 2  | David     | Miller   |
| 3  | John      | Doe      |
+----+-----------+----------+
3 rows in set (0.00 sec)

以下是处理group_concat函数的新行分隔符的查询 –

mysql> select group_concat(concat_ws(' ',FirstName, LastName) SEPARATOR "\r  
") from DemoTable;

这将产生以下输出 –

+-------------------------------------------------------------------+
| group_concat(concat_ws(' ',FirstName, LastName) SEPARATOR "\r  
") |
+-------------------------------------------------------------------+
| John Smith David Miller John Doe                                  |
+-------------------------------------------------------------------+
1 row in set (0.00 sec)

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