如何将MySQL不同的查询结果连接成字符串？
使用MySQL的group_concat()函数进行串联。让我们首先创建一个表-
mysql> create table DemoTable -> ( -> Subject varchar(10) -> );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values('C');
mysql> insert into DemoTable values('C++');
mysql> insert into DemoTable values('C++');
mysql> insert into DemoTable values('MongoDB');
mysql> insert into DemoTable values('MySQL');
mysql> insert into DemoTable values('MongoDB');
mysql> insert into DemoTable values('MongoDB');
mysql> insert into DemoTable values('Java');
mysql> insert into DemoTable values('Java');
Display all records from the table using select statement:mysql> select *from DemoTable;
输出结果
这将产生以下输出-
+---------+ | Subject | +---------+ | C | | C++ | | C++ | | MongoDB | | MySQL | | MongoDB | | MongoDB | | Java | | Java | +---------+ 9 rows in set (0.00 sec)
以下是将SQL不同的查询结果串联为字符串的查询-
mysql> select group_concat(tbl.sub) from (select Subject sub from DemoTable group by Subject ) tbl;
输出结果
这将产生以下输出-
+--------------------------+ | group_concat(tbl.sub) | +--------------------------+ | C,C++,MongoDB,MySQL,Java | +--------------------------+ 1 row in set (0.04 sec)