Answer
LEAD returns a value from a later row in the window ordering. • An offset chooses how many rows ahead to read. • A default can be supplied when no later row exists. • It avoids a self join for many next-row comparisons.
💡 SQL Example
SELECT ordered_at, amount, LEAD(amount) OVER (ORDER BY ordered_at) AS next_amount FROM payments;
Result
Each payment with the following payment amount
⚡ Quick Revision
LEAD reads a value from a later ordered row.