sql - postgresql:从 Char Varying 字段中提取多个值

Question

我在 PostgreSQL 中有一个类型为字符变化的字段 [] 这里存储的是扇区，有些客户没有数据，其他客户有1到多个扇区，最终看起来像这样

**Customer**  ABC        
**Sector** ,Exh: Food Trade,Exh: Beverage Trade,Evt: Sporting

有人知道我如何查询每个值吗？为我提供每个客户的独特值(value)

**Customer** ABC **sector** Exh:Food Trade,
**Customer** ABC **sector** Exh:Beverage Trade
**Customer** ABC **Sector** Evt:Sporting

Answer 1

尝试使用unnest .

测试数据

CREATE TABLE t (customer text, sector text[]);
INSERT INTO t VALUES 
('ABC',string_to_array(',Exh: Food Trade,Exh: Beverage Trade,Evt: Sporting',','));

查询

SELECT customer, unnest(sector) FROM t;
 customer |       unnest        
----------+---------------------
 ABC      | 
 ABC      | Exh: Food Trade
 ABC      | Exh: Beverage Trade
 ABC      | Evt: Sporting
(4 Zeilen)

编辑:使用 CTE 删除空元素(见评论)

WITH j AS (
SELECT customer, unnest(sector) as sector FROM t 
) SELECT * FROM j WHERE sector <> '';

 customer |       sector        
----------+---------------------
 ABC      | Exh: Food Trade
 ABC      | Exh: Beverage Trade
 ABC      | Evt: Sporting
(3 Zeilen)