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hardDSA

What do the LAG and LEAD window functions do?

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01

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Explain LAG and LEAD.

laglead
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LAG(col, n) accesses a value from n rows before the current row in the window; LEAD(col, n) from n rows after. They're ideal for comparing a row to its neighbors — e.g. computing day-over-day differences or detecting changes.

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SQLLAG/LEAD Revenue Analysis
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