SQL中group_concat函数，用符号连接查询分组里字段值

MySQL中group_concat函数
完整的语法如下：
group_concat([DISTINCT] 要连接的字段 [Order BY ASC/DESC 排序字段] [Separator '分隔符'])

基本查询

[sql] view plain copy print ?

1. mysql> select * from aa;
2. +------+------+
3. | id| name |
4. +------+------+
5. |1 | 10|
6. |1 | 20|
7. |1 | 20|
8. |2 | 20|
9. |3 | 200 |
10. |3 | 500 |
11. +------+------+
12. 6 rowsinset (0.00 sec)

mysql> select * from aa;
 +------+------+
 | id| name |
 +------+------+
 |1 | 10|
 |1 | 20|
 |1 | 20|
 |2 | 20|
 |3 | 200  |
 |3 | 500  |
 +------+------+
 6 rows in set (0.00 sec)

以id分组，把name字段的值打印在一行，逗号分隔(默认)

[sql] view plain copy print ?

1. mysql> select id,group_concat(name) from aa groupby id;
2. +------+--------------------+
3. | id| group_concat(name) |
4. +------+--------------------+
5. |1 | 10,20,20|
6. |2 | 20 |
7. |3 | 200,500|
8. +------+--------------------+
9. 3 rowsinset (0.00 sec)

mysql> select id,group_concat(name) from aa group by id;
 +------+--------------------+
 | id| group_concat(name) |
 +------+--------------------+
 |1 | 10,20,20|
 |2 | 20 |
 |3 | 200,500|
 +------+--------------------+
 3 rows in set (0.00 sec)

以id分组，把name字段的值打印在一行，分号分隔

[sql] view plain copy print ?

1. mysql> select id,group_concat(name separator ';') from aa groupby id;
2. +------+----------------------------------+
3. | id| group_concat(name separator ';') |
4. +------+----------------------------------+
5. |1 | 10;20;20 |
6. |2 | 20|
7. |3 | 200;500 |
8. +------+----------------------------------+
9. 3 rowsinset (0.00 sec)

mysql> select id,group_concat(name separator ';') from aa group by id;
 +------+----------------------------------+
 | id| group_concat(name separator ';') |
 +------+----------------------------------+
 |1 | 10;20;20 |
 |2 | 20|
 |3 | 200;500  |
 +------+----------------------------------+
 3 rows in set (0.00 sec)

以id分组，把去冗余的name字段的值打印在一行，

[sql] view plain copy print ?

1. mysql> select id,group_concat(distinctname) from aa groupby id;
2. +------+-----------------------------+
3. | id| group_concat(distinctname) |
4. +------+-----------------------------+
5. |1 | 10,20|
6. |2 | 20 |
7. |3 | 200,500 |
8. +------+-----------------------------+
9. 3 rowsinset (0.00 sec)

mysql> select id,group_concat(distinct name) from aa group by id;
 +------+-----------------------------+
 | id| group_concat(distinct name) |
 +------+-----------------------------+
 |1 | 10,20|
 |2 | 20  |
 |3 | 200,500 |
 +------+-----------------------------+
 3 rows in set (0.00 sec)

以id分组，把name字段的值打印在一行，逗号分隔，以name排倒序

[sql] view plain copy print ?

1. mysql> select id,group_concat(nameorderbynamedesc) from aa groupby id;
2. +------+---------------------------------------+
3. | id| group_concat(nameorderbynamedesc) |
4. +------+---------------------------------------+
5. |1 | 20,20,10 |
6. |2 | 20|
7. |3 | 500,200|
8. +------+---------------------------------------+
9. 3 rowsinset (0.00 sec)