使用 MySQL GROUP BY 按组列出所有行?
mysqlmysqli database更新于 2025/9/16 9:48:17
要按组列出所有行，您可以使用 GROUP_CONCAT()。让我们首先创建一个表 −
mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(20), Value varchar(100) ); Query OK, 0 rows affected (0.62 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable(Name,Value) values('John','John');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable(Name,Value) values('Carol','Carol');
Query OK, 1 row affected (0.21 sec)
mysql> insert into DemoTable(Name,Value) values('John','Works');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(Name,Value) values('Carol','Works');
Query OK, 1 row affected (0.22 sec)
mysql> insert into DemoTable(Name,Value) values('John','At');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable(Name,Value) values('Carol','At');
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable(Name,Value) values('John','Amazon');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable(Name,Value) values('Carol','Google');
Query OK, 1 row affected (0.16 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 | Name | Value | +----+-------+--------+ | 1 | John | John | | 2 | Carol | Carol | | 3 | John | Works | | 4 | Carol | Works | | 5 | John | At | | 6 | Carol | At | | 7 | John | Amazon | | 8 | Carol | Google | +----+-------+--------+ 8 rows in set (0.00 sec)
以下是按组列出所有行的查询。这里将获取 ‘John’ 的值，即 “John Works At Amazon，ID 为 1、3、5、7。同样，它适用于 ‘Carol’ −
mysql> select Name, GROUP_CONCAT(Value SEPARATOR ' ') AS `Complete_Status` from DemoTable group by Name;
这将产生以下输出 −
+-------+-----------------------+ | Name | Complete_Status | +-------+-----------------------+ | Carol | Carol Works At Google | | John | John Works At Amazon | +-------+-----------------------+ 2 rows in set (0.00 sec)
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