Postgres 12

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CREATE TABLE tb_route
(
    from_city_name            CHARACTER VARYING(120) NOT NULL ,
    to_city_name              CHARACTER VARYING(120) NOT NULL ,
    km_distance_num           NUMERIC NOT NULL ,
    CONSTRAINT pk_route PRIMARY KEY (from_city_name, to_city_name)
);

CREATE TABLE


INSERT INTO tb_route VALUES
  ('Saint Jean Pied de Port','Roncesvalles',25.7),
  ('Somport','Jaca',30.5),
  ('Roncesvalles','Zubiri',21.5),
  ('Jaca','Arrés',25),
  ('Zubiri','Pamplona/Iruña',20.4),
  ('Arrés','Ruesta',28.7),
  ('Pamplona/Iruña','Puente la Reina/Gares',24),
  ('Ruesta','Sangüesa',21.8),
  ('Puente la Reina/Gares','Estella/Lizarra',22),
  ('Sangüesa','Monreal',27.25),
  ('Estella/Lizarra','Torres del Río',29),
  ('Monreal','Puente la Reina/Gares',31.1),
  ('Torres del Río','Logroño',20),
  ('Logroño','Nájera',29.6),
  ('Nájera','Santo Domingo de la Calzada',21),
  ('Santo Domingo de la Calzada','Belorado',22.7),
  ('Belorado','Agés',27.4),
  ('Agés','Burgos',23),
  ('Burgos','Hontanas',31.1),
  ('Hontanas','Boadilla del Camino',28.5),
  ('Boadilla del Camino','Carrión de los Condes',24.6),
  ('Carrión de los Condes','Terradillos de los Templarios',26.6),
  ('Terradillos de los Templarios','El Burgo Ranero',30.6),
  ('El Burgo Ranero','León',37.1),
  ('León','San Martín del Camino',25.9),
  ('San Martín del Camino','Astorga',24.2),
  ('Astorga','Foncebadón',25.9),
  ('Foncebadón','Ponferrada',27.3),
  ('Ponferrada','Villafranca del Bierzo',24.1),
  ('Villafranca del Bierzo','O Cebreiro',28.4),
  ('O Cebreiro','Triacastela',21.1),
  ('Triacastela','Sarria',18.3),
  ('Sarria','Portomarín',22.4),
  ('Portomarín','Palas de Rei',25),
  ('Palas de Rei','Arzúa',28.8),
  ('Arzúa','Pedrouzo',19.1),
  ('Pedrouzo','Santiago de Compostela',20),
  ('Bayona','Ustaritz',14.3),
  ('Ustaritz','Urdax',21.2),
  ('Urdax','Elizondo',18.8),
  ('Elizondo','Berroeta',9.7),
  ('Berroeta','Olagüe',20.4),
  ('Olagüe','Pamplona/Iruña',25),
  ('Irún','Hernani',26.6),
  ('Hernani','Tolosa',18.9),
  ('Tolosa','Zerain',33),
  ('Zerain','Salvatierra/Agurain',28),
  ('Salvatierra/Agurain','Vitoria/Gasteiz',27.4),
  ('Vitoria/Gasteiz','La Puebla de Arganzón',18.5),
  ('La Puebla de Arganzón','Haro',31),
  ('Haro','Santo Domingo de la Calzada',20),
  ('Bayona','Irún',33.8),
  ('Tolosa','Zegama',37.9),
  ('Zegama','Salvatierra/Agurain',20.1),
  ('La Puebla de Arganzón','Miranda del Ebro',22.3),
  ('Miranda del Ebro','Pancorbo',16.7),
  ('Pancorbo','Briviesca',23.4),
  ('Briviesca','Monasterio de Rodilla',19.8),
  ('Monasterio de Rodilla','Burgos',28.5);

INSERT 0 59


with recursive cte as (
    select 
        from_city_name, 
	to_city_name, 
	km_distance_num, 
	array[from_city_name::text, to_city_name::text] path
    from tb_route
    where from_city_name = 'Saint Jean Pied de Port'
    union all
    select 
        r.from_city_name, 
	r.to_city_name, 
	c.km_distance_num + r.km_distance_num,
	c.path || r.to_city_name::text
    from tb_route r
    inner join cte c on c.to_city_name = r.from_city_name
    where not r.to_city_name = any(c.path) and c.from_city_name <> 'Santiago de Compostela'
)

select path[1] from_city_name, to_city_name, km_distance_num, array_to_string(path, ' > ') path
from cte
where to_city_name = 'Santiago de Compostela';


from_city_name
to_city_name
km_distance_num
path


Saint Jean Pied de Port
Santiago de Compostela
775.3
Saint Jean Pied de Port > Roncesvalles > Zubiri > Pamplona/Iruña > Puente la Reina/Gares > Estella/Lizarra > Torres del Río > Logroño > Nájera > Santo Domingo de la Calzada > Belorado > Agés > Burgos > Hontanas > Boadilla del Camino > Carrión de los Condes > Terradillos de los Templarios > El Burgo Ranero > León > San Martín del Camino > Astorga > Foncebadón > Ponferrada > Villafranca del Bierzo > O Cebreiro > Triacastela > Sarria > Portomarín > Palas de Rei > Arzúa > Pedrouzo > Santiago de Compostela



SELECT 1