PostgreSql 合並多行記錄

需求描述：

A表有如下數據

id

1

2

3

4

B表有如下數據

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

 

A表和B表通過id關聯，需要查詢結果如下：

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

查詢語句如下：

 
             
              
              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