MySQL merges a field in the record

Merge a field in a single record: Concat ()
If for the user table, the following:

Age

ID	class	name
1	1001	Zh	18
2	1001	En	19
3	1002	Cs	18
4	1002	Jp	19

If you want to display name and age as a field, there are:

select id, class, concat(name, ": ", age) as name_age from user;

Results:

ID	class	Name_age
1	1001	Zh:18
2	1001	En:19
3	1002	Cs:18
4	1002	Jp:19

Two merge some fields from multiple records: Group_coacat ()
Still on the user table above, if grouped by grade, and the name and age are all combined in one column, there are:

select class, group_concat(name, ":", age) as name_age from user group by class;

The result is:

class	Name_age
1001	Zh:18,en:19
1002	Cs:18,jp:19

Using the Group_coacat () method, by default, is split with "," and if you want to split with other characters you can use "separator", such as:

select class, group_concat(name, ":", age separator ";") as name_age from user group by class;

The result is:

class	Name_age
1001	Zh:18;en:19
1002	Cs:18;jp:19

MySQL merges a field in the record