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create table events ( id serial, user_id int, event_type varchar, event_time timestamp ); insert into events (user_id, event_type, event_time) values (1, 'display', now()), (1, 'display', now()),(1, 'click', now()),(1, 'display', now()), (2, 'display', now()), (2, 'click', now()); select clicks.user_id, count(display.id) from events clicks left join events display on display.user_id = clicks.user_id and display.event_type = 'display' and display.id < clicks.id -- should be changed to time comparsion where clicks.event_type = 'click' group by clicks.user_id