Exercise: LAG, LEAD, and Row Comparison

Write a query that uses LAG() over streams ordered by started_at ascending to return the previous stream's started_at alongside each row. Return stream_id, started_at, and prev_started_at. Order by started_at.

Write a query that uses LEAD() over streams ordered by started_at ascending to return the next stream's started_at alongside each row. Return stream_id, started_at, and next_started_at. Order by started_at. Limit to the first 5 rows of output.

Write a query that uses LAG(started_at) partitioned by user_id to compute the gap in days between each of alice_m's (user_id = 1) consecutive streams. Return stream_id, started_at, and days_gap (integer day component of the interval). Order by started_at.