查找重复项并在sql中合并其值

Question

我有一个数据库表，其中包含学校和姓名的列表：

school    name    point
------------------------
first     dani    good
first     dani    precise
third     John    nice
first     dani    pro
third     John    cute

我想以每个学校/名称组合的唯一记录结束，并合并点值，如下所示：

school    name    point
--------------------------------------
first     dani    good and precise and pro
third     John    cute and nice

Answer 1

您可以像这样使用GROUP_CONCAT来获得结果：

SELECT school, name, GROUP_CONCAT(point SEPARATOR ' and ') points
FROM table
GROUP BY school, name

如果可以，并且您要用结果替换实际的表，则使用另一个名称tmptable创建相同的表。

INSERT INTO tmptable
SELECT school, name, GROUP_CONCAT(point SEPARATOR ' and ') points
FROM table
GROUP BY school, name;

DROP TABLE table;
RENAME TABLE tmptable TO table;

在这里，您可以在sqlfiddle中看到结果

Answer 2

这是一个适合您的样本

还有一个新的DISTINCT

SELECT
  school,
  `name`,
  GROUP_CONCAT( `point` SEPARATOR ' and ')
FROM ( SELECT DISTINCT school,`name`, `point` FROM groupme) AS result
GROUP BY school,`NAME`;

---

SELECT
  school,
  `name`,
  GROUP_CONCAT( `point` SEPARATOR ' and ')
FROM groupme
GROUP BY school,`name`;

样品

MariaDB [mysql]> select * from groupme;
+----+--------+------+---------+
| id | school | name | point   |
+----+--------+------+---------+
|  1 | first  | dani | good    |
|  2 | first  | dani | precise |
|  3 | third  | John | nice    |
|  4 | first  | dani | pro     |
|  5 | third  | John | cute    |
+----+--------+------+---------+
5 rows in set (0.01 sec)

MariaDB [mysql]> SELECT school, `name` , GROUP_CONCAT( `point` SEPARATOR ' and ')
    -> FROM groupme
    -> GROUP BY school,`name`;
+--------+------+------------------------------------------+
| school | name | GROUP_CONCAT( `point` SEPARATOR ' and ') |
+--------+------+------------------------------------------+
| first  | dani | good and precise and pro                 |
| third  | John | nice and cute                            |
+--------+------+------------------------------------------+
2 rows in set (0.00 sec)

MariaDB [mysql]>

Answer 3

使用@ebahi的答案：

将查询更改为@fuzzytree中提到的内容：

SELECT school, name, GROUP_CONCAT(distinct point SEPARATOR ' and ') points
FROM table
GROUP BY school, name

sqlfiddle查看结果