MySQL PgSQL realizes the merging of multiple lines of records into one line, grouping and merging, and dividing with specified characters

Database server environment

database	edition
mysql	5.7
PostgreSQL	10.10

Original table structure and data

id	name	gender	major
1	Zhang San	male	Basketball
2	Zhang San	male	football
3	Li Si	Woman	swimming
4	Xiaozhou	Woman	running
5	The king 2	male	Bodybuilding
6	Xiaozhou	Woman	Tennis
7	Zhang San	male	football

mysql

SQL

select demo_table.name, group_concat(major separator ',') as combine_name
from demo_table
group by name

result

name	combine_name
Xiaozhou	running , Tennis
Zhang San	Basketball , football , football
Li Si	swimming
The king 2	Bodybuilding

duplicate removal

select demo_table.name, group_concat(distinct major separator ',') as combine_name
from demo_table
group by name

Query results after de duplication

name	combine_name
Xiaozhou	Tennis , running
Zhang San	Basketball , football
Li Si	swimming
The king 2	Bodybuilding

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pgsql

SQL

select name ,
       array_to_string(array (select unnest(array_agg(major))), ',') as combination_name
from demo_table
group by name

result

name	combination_name
Zhang San	Basketball , football , football
Li Si	swimming
Xiaozhou	running , Tennis
The king 2	Bodybuilding

duplicate removal

select name ,
       array_to_string(array (select unnest(array_agg(distinct major))), ',') as combination_name
from demo_table
group by name

Results after weight removal

name	combination_name
Xiaozhou	Tennis , running
Zhang San	Basketball , football
Li Si	swimming
The king 2	Bodybuilding

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