PostgreSQL常用字符串分割函数整理汇总

SELECT SPLIT_PART('A,B,C', ',', 2);  -- 返回B

select split_part( current_date::text,'-',1) as year ,
       split_part( current_date::text,'-',2) as  month,
       split_part( current_date::text,'-',3) as day

SELECT string_to_array('xx~^~yy~^~zz', '~^~');       -- {xx,yy,zz}
SELECT string_to_array('xx~^~yy~^~zz', '~^~', 'yy'); -- {xx,,zz}

SELECT t as name
FROM unnest(string_to_array('john,smith,jones', ',')) AS t;       

postgres=# SELECT regexp_split_to_array('foo  bar baz', '\s+');
 regexp_split_to_array 
-----------------------
 {foo,bar,baz}
(1 row)

SELECT t as item
FROM regexp_split_to_table('foo    bar,baz', E'[\\s,]+') AS t;

select regexp_split_to_array('the,quick,brown;fox;jumps', '[,;]') AS subelements
-- 返回 {the,quick,brown,fox,jumps}

select regexp_matches('hello how are you', 'h[a-z]*', 'g')  
 as Words_starting_with_h

select regexp_replace('yellow submarine', 'y[a-z]*w','blue');
-- 返回结果：blue submarine