postgresql：从字符变化字段中提取多个值

Question

I have a field in PostgreSQL of type character varying [] stored here is sector, some customers have no data, others have 1 to many sectors which ends up looking like this

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

does any one know how I could query this out per value? to give me the unique values per customer

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

Answer 1

Try using unnest .

Test Data

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

Query

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

Edit : Getting rid of empty elements using a CTE (see comments)

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)