PostgreSQL合并多行数据为一行，string_agg函数

通过id列来聚合belong_user_saved列，应用string_agg函数，只要id一样则把第二列通过逗号连接起来

聚合前：

聚合后：

SELECT 
	C.ID,
	string_agg(u.name::varchar,',') belong_user_saved
FROM
	customer C 
	left join customer_territory ct on ct.customer = c.id
	left join user_territory ut on ct.territory = ut.territory
	left join user_info u on ut.user_info = u.id
WHERE
	C.is_deleted = FALSE 
	and ct.is_deleted = false
	and ut.is_deleted = false
	and u.is_deleted = false
	and u.enable = true
	AND C.is_active = TRUE 
	AND C.record_type IN (
	'hco',
	'pharmacy',
	'distributor')
	group  by C.ID

进阶版，通过having语句摘出来所有出现过两次以上的

	SELECT 
	C.ID,
	string_agg(u.name::varchar,','),
	count(C.ID) as cnt
FROM
	customer C 
	left join customer_territory ct on ct.customer = c.id
	left join user_territory ut on ct.territory = ut.territory
	left join user_info u on ut.user_info = u.id
WHERE
	C.is_deleted = FALSE 
	and ct.is_deleted = false
	and ut.is_deleted = false
	and u.is_deleted = false
	and u.enable = true
	AND C.is_active = TRUE 
	AND C.record_type IN (
	'hco',
	'pharmacy',
	'distributor')
	group  by C.ID
	HAVING count(C.ID)>=2