我们可以按一列分组并选择MySQL中的所有数据吗？
是的，您可以为此使用group_concat()。让我们首先创建一个表-
mysql> create table groupByOneSelectAll -> ( -> StudentDetails varchar(100), -> StudentName varchar(100) -> );
以下是使用insert命令在表中插入一些记录的查询-
mysql> insert into groupByOneSelectAll values('StudentFirstName','John');
mysql> insert into groupByOneSelectAll values('StudentFirstName','Chris');
mysql> insert into groupByOneSelectAll values('StudentFirstName','Robert');
mysql> insert into groupByOneSelectAll values('StudentFirstName','Bob');
mysql> insert into groupByOneSelectAll values('StudentFirstName','David');以下是使用select语句显示表中所有记录的查询-
mysql> select * from groupByOneSelectAll;
这将产生以下输出-
+------------------+-------------+ | StudentDetails | StudentName | +------------------+-------------+ | StudentFirstName | John | | StudentFirstName | Chris | | StudentFirstName | Robert | | StudentFirstName | Bob | | StudentFirstName | David | +------------------+-------------+ 5 rows in set (0.00 sec)
以下是按单个列分组的查询-
mysql> select StudentDetails,group_concat(StudentName) from groupByOneSelectAll group by StudentDetails;
这将产生以下输出-
+------------------+-----------------------------+ | StudentDetails | group_concat(StudentName) | +------------------+-----------------------------+ | StudentFirstName | John,Chris,Robert,Bob,David | +------------------+-----------------------------+ 1 row in set (0.05 sec)