SQLLAGLEADwindow
What are LAG and LEAD in SQL? Neighbouring rows in a window for beginners
LAG and LEAD return the value from the **previous** or **next** row of a window. Plain words: day-over-day delta, time-to-next-event, price change — tasks that previously required self-joining a table. With tables and common pitfalls.
1 min qariSQL · LAG · LEAD · window · tutorial
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LAGandLEADare window functions that look at neighbouring rows.LAGreturns the previous row's value,LEADthe next. They unlock day-over-day deltas, time-to-next-event, price changes — all the things that previously required self-joins.This article is currently in Russian. The full English translation is on the way.