PostgreSql 合併多行記錄

需求描述：

A表有以下數據

id

1

2

3

4

B表有以下數據

id	name
1	aaa
1	bbb
1	ccc
2	aa
2	bb
3	c

 

A表和B表經過id關聯，須要查詢結果以下：

id	name
1	aaa,bbb,ccc
2	aa,bb
3	c
4

查詢語句以下：

 
     
      
      SELECT a.id,array_to_string(array(     
         SELECT b.name  FROM  db_xx."B" b  WHERE b.id=a.id      
       ), ',') as name   
      from db_xx."A" a   
      order by a.id
SELECT a.id,array_to_string(array(
   SELECT b.name  FROM  db_xx."B" b  WHERE b.id=a.id
 ), ',') as name
from db_xx."A" a
order by a.id