Дмитрий Телепнев

with recursive table_recursive as (
	with "table" as (
		select *
		from (
			values('x','a'),
			('a','b'),
			('b','c'),
			('c','d'),
			('n','k'),
			('k','l')
		) as _(main,"cross")
	)
	select *, t.main || ' -> ' || t."cross" as "path"
	from "table" as t
	
	union
	
	select t_r.main, t."cross", t_r."path" || ' -> ' || t."cross" as "path"
	from table_recursive t_r
	join "table" t on t.main = t_r."cross"
)
select t_r.*
from table_recursive t_r
where
	t_r."main" not in (select "cross" from table_recursive)
	and t_r."cross" not in (select "main" from table_recursive)

select
    table1.user_id, count(table1.amount)
from table1
join (
    select
        user_id, min(created_at) minimal_date
    from table1
    group by user_id
)dates on dates.user_id = table1.user_id
    and table1.created_at between dates.minimal_date and (dates.minimal_date + interval '5d')
group by table1.user_id

select * from car_orders where start_end_range && daterange('2018-01-01', '2018-01-02')

select to_tsvector('pg_catalog.english', 'яблоко'), to_tsquery('pg_catalog.russian', 'Яблоко')