STDDEV

1
SELECT
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  ROUND(AVG(price), 2) as avg_price,
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  ROUND(STDDEV(price), 2) as stddev_price
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FROM products;

1
SELECT
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  category,
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  COUNT(*) as count,
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  ROUND(AVG(price), 2) as avg_price,
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  ROUND(STDDEV(price), 2) as stddev_price,
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  ROUND(STDDEV(price) / AVG(price) * 100, 2) as cv_percent
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FROM products
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GROUP BY category
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ORDER BY cv_percent DESC;

1
SELECT
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  STDDEV_SAMP(score) as sample_stddev,
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  STDDEV_POP(score) as population_stddev
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FROM test_scores;