SIGN

1
SELECT SIGN(-10) AS neg, SIGN(0) AS zero, SIGN(10) AS pos;

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SELECT product, current - previous AS change,
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  CASE SIGN(current - previous)
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    WHEN 1 THEN 'Increase'
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    WHEN -1 THEN 'Decrease'
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    ELSE 'No Change'
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  END AS trend
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FROM inventory;

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SELECT account,
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  CASE SIGN(balance)
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    WHEN 1 THEN 'Profit'
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    WHEN -1 THEN 'Loss'
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    ELSE 'Break Even'
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  END AS status
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FROM accounts;