LAG & LEAD Comparison — Solution & ExplanationProblems / LAG & LEAD Comparison / EditorialApproachLAG and LEAD are offset functions that access rows at a fixed distance from the current row.

LAG(price, 1): Returns the price from 1 row before the current row within the partition.

LEAD(price, 1): Returns the price from 1 row after the current row.

Partition: By ticker so each stock is handled independently.

Order: By date to define what "previous" and "next" mean chronologically.

Boundary rows return NULL because there is no preceding/following row to reference.Hints

LAG(col, 1) looks at the previous row, LEAD(col, 1) looks at the next row.

PARTITION BY ticker ensures you don't mix data across tickers.

The first row in each partition has no LAG value (NULL), the last has no LEAD value (NULL).

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