create table answers (id int, text varchar(100), question_id int);

create table answer_tags (id int, answer_id int, tag_id int);

create table tags (id int, text varchar(100));

insert into questions values (1, 'question1'), (2, 'question2'), (3, 'question3'), (4, 'question4'), (5, 'question5');

insert into answers values (1, 'answer1', 1), (2, 'answer2', 2), (3, 'answer3', 3), (4, 'answer4', 4), (5, 'answer5', 5), (6, 'answer6', 1);

insert into tags values (1, 'tag1'), (2, 'tag2'), (3, 'tag3'), (4, 'tag4'), (5, 'tag5');

insert into answer_tags values (1,1,1), (2,1,2), (3,1,3), (4,1,4), (5,2,2), (6,2,3), (7,2,4), (8,3,3), (9,3,4), (10,4,4), (11,5,3), (12,5,4), (13,5,5);

(

SELECT ARRAY["t"."id"] "id"

FROM "tags" "t"

UNION ALL

SELECT "c"."id" || "t"."id" "id"

FROM "cte" "c"

INNER JOIN "tags" "t"

ON "t"."id" > (SELECT max("un"."e")

FROM unnest("c"."id") "un" ("e"))

)

SELECT "c"."id" "id",

(SELECT array_agg("t"."text")

FROM unnest("c"."id") "un" ("e")

INNER JOIN "tags" "t"

ON "t"."id" = "un"."e") "text",

count(*) "count"

FROM "cte" "c"

INNER JOIN (SELECT array_agg("at"."tag_id" ORDER BY "at"."tag_id") "id"

FROM "answer_tags" "at"

GROUP BY at.answer_id) "x"

ON "x"."id" @> "c"."id"

WHERE array_length("c"."id", 1) > 1

GROUP BY "c"."id"

HAVING count(*) > 1;