sql按照分组返回数据

数据样本包含分组信息；

create table t2 ( 
    id int primary key,
    gid    char,
    col1    int,
    col2    int
);

-- 插入数据

insert into t2 values 
(1,'A',31,6),
(2,'B',25,83),
(3,'C',76,21),
(4,'D',63,56),
(5,'E',3,17),
(6,'A',29,97),
(7,'B',88,63),
(8,'C',16,22),
(9,'D',25,43),
(10,'E',45,28),
(11,'A',2,78),
(12,'B',30,79),
(13,'C',96,73),
(14,'D',37,40),
(15,'E',14,86),
(16,'A',32,67),
(17,'B',84,38),
(18,'C',27,9),
(19,'D',31,21),
(20,'E',80,63);
           

现在想要按照gid进行分组获取每个分组中col1, MySQL的group by更多是用于分类统计。

这样就可以按照gid将col1的值连接起来。