LAG

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SELECT
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  month,
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  revenue,
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  LAG(revenue) OVER (ORDER BY month) as prev_month_revenue,
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  revenue - LAG(revenue) OVER (ORDER BY month) as revenue_change
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FROM monthly_sales;

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SELECT
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  month,
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  revenue,
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  LAG(revenue, 1, revenue) OVER (ORDER BY month) as prev_revenue,
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  ROUND((revenue - LAG(revenue, 1, revenue) OVER (ORDER BY month)) /
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        NULLIF(LAG(revenue, 1, revenue) OVER (ORDER BY month), 0) * 100, 2) as pct_change
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FROM monthly_sales;

1
SELECT
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  customer_id,
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  order_date,
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  order_total,
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  LAG(order_date) OVER (
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    PARTITION BY customer_id
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    ORDER BY order_date
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  ) as prev_order_date,
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  DATEDIFF('DAY',
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    LAG(order_date) OVER (PARTITION BY customer_id ORDER BY order_date),
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    order_date
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  ) as days_between_orders
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FROM orders;