PostgreSQL 字符串拆分与合并案例

with person_name as (
  select c.id,
      array_to_string(array_agg(distinct p.c_name), ' , ') as p_name
  from biz_notification_config c
       join biz_notification_person p
         on p.id =
           any (string_to_array(c.persons, ',')::int[])
  group by c.id
),
   group_name as (
     select c.id,
        array_to_string(array_agg(distinct g.c_name), ' , ') as g_name
     from biz_notification_config c
         join biz_notification_group g
            on g.id = any (string_to_array(c.c_groups, ',')::int[])
     group by c.id
   )
select config.*, person_name.p_name, group_name.g_name
from biz_notification_config config
     left join person_name
          on config.id = person_name.id
     left join group_name
          on config.id = group_name.id;

DELIMITER $$ 
 
CREATE DEFINER=`root`@`%` FUNCTION `func_get_split_string_total`(
f_string VARCHAR(1000),f_delimiter VARCHAR(5)
) RETURNS INT(11)
BEGIN
 -- Get the total number of given string.
 RETURN 1+(LENGTH(f_string) - LENGTH(REPLACE(f_string,f_delimiter,'')));
END$$ 
 
DELIMITER ;

DELIMITER $$ 
 
CREATE DEFINER=`root`@`%` FUNCTION `func_get_split_string`(
f_string VARCHAR(1000),f_delimiter VARCHAR(5),f_order INT) RETURNS VARCHAR(255) CHARSET utf8
BEGIN
 -- Get the separated number of given string.
 DECLARE result VARCHAR(255) DEFAULT '';
 SET result = REVERSE(SUBSTRING_INDEX(REVERSE(SUBSTRING_INDEX(f_string,f_delimiter,f_order)),f_delimiter,1));
 RETURN result;
END$$ 
 
DELIMITER ;

DELIMITER $$ 
 
CREATE PROCEDURE `sp_print_result`(
 IN f_string VARCHAR(1000),IN f_delimiter VARCHAR(5)
)
BEGIN
 -- Get the separated string.
 DECLARE cnt INT DEFAULT 0;
 DECLARE i INT DEFAULT 0;
 SET cnt = func_get_split_string_total(f_string,f_delimiter);
 DROP TABLE IF EXISTS tmp_print;
 CREATE TEMPORARY TABLE tmp_print (v_text varchar(200) NOT NULL);
 WHILE i < cnt
 DO
  SET i = i + 1;
  INSERT INTO tmp_print(v_text) VALUES (func_get_split_string(f_string,f_delimiter,i));
 END WHILE;
 SELECT * FROM tmp_print;
 
END$$ 
 
DELIMITER ;

CALL sp_print_result('love,you,hate,number',',');
query result
v_text 
love 
you 
hate 
number 

 create or replace function split_to_string(
IN f_string text, 
IN f_delimiter varchar(10)
) returns setof text as
$ytt$
 declare cnt int;
 declare i int;
 declare v_result text;
 begin
   i := 1;
   cnt := length(f_string) - length(replace(f_string,f_delimiter,''))+1;
   while i <= cnt
   loop
    v_result := split_part(f_string,f_delimiter,i);
 return next v_result;
    i := i + 1;
   end loop; 
 
 end;
$ytt$ language plpgsql;

t_girl=# select split_to_string('love,you,hate,number',',') as result;
 result 
--------
 love
 you
 hate
 number
(4 rows)

t_girl=# SELECT ytt FROM regexp_split_to_table('love,you,hate,number', E',+') AS ytt;
 ytt  
--------
 love
 you
 hate
 number
(4 rows) 
 
t_girl=# 

t_girl=# with recursive ytt(f1,f2) as (
values (0,' '::text) 
union all 
select f1+1,split_part('love,you,hate,number',',',f1+1) from ytt where f1 < 20 
) 
select f2 as result from ytt where f1 >=1 and f1 <= length('love,you,hate,number')-length(replace('love,you,hate,number',',',''))+1;
 result 
--------
 love
 you
 hate
 number
(4 rows)
 
Time: 0.742 ms