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105 lines
5.8 KiB
Markdown
105 lines
5.8 KiB
Markdown
---
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slug: /en/sql-reference/aggregate-functions/reference/exponentialTimeDecayedMax
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sidebar_position: 135
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title: exponentialTimeDecayedMax
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---
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## exponentialTimeDecayedMax
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Returns the maximum of the computed exponentially smoothed moving average at index `t` in time with that at `t-1`.
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**Syntax**
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```sql
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exponentialTimeDecayedMax(x)(value, timeunit)
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```
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**Arguments**
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- `value` — Value. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
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- `timeunit` — Timeunit. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md), [DateTime](../../data-types/datetime.md), [DateTime64](../../data-types/datetime64.md).
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**Parameters**
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- `x` — Half-life period. [Integer](../../../sql-reference/data-types/int-uint.md), [Float](../../../sql-reference/data-types/float.md) or [Decimal](../../../sql-reference/data-types/decimal.md).
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**Returned values**
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- Returns the maximum of the exponentially smoothed weighted moving average at `t` and `t-1`. [Float64](../../data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT
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value,
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time,
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round(exp_smooth, 3),
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bar(exp_smooth, 0, 5, 50) AS bar
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FROM
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(
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SELECT
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(number = 0) OR (number >= 25) AS value,
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number AS time,
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exponentialTimeDecayedMax(10)(value, time) OVER (ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS exp_smooth
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FROM numbers(50)
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);
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```
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Result:
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```response
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┌─value─┬─time─┬─round(exp_smooth, 3)─┬─bar────────┐
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1. │ 1 │ 0 │ 1 │ ██████████ │
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2. │ 0 │ 1 │ 0.905 │ █████████ │
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3. │ 0 │ 2 │ 0.819 │ ████████▏ │
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4. │ 0 │ 3 │ 0.741 │ ███████▍ │
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5. │ 0 │ 4 │ 0.67 │ ██████▋ │
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6. │ 0 │ 5 │ 0.607 │ ██████ │
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7. │ 0 │ 6 │ 0.549 │ █████▍ │
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8. │ 0 │ 7 │ 0.497 │ ████▉ │
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9. │ 0 │ 8 │ 0.449 │ ████▍ │
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10. │ 0 │ 9 │ 0.407 │ ████ │
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11. │ 0 │ 10 │ 0.368 │ ███▋ │
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12. │ 0 │ 11 │ 0.333 │ ███▎ │
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13. │ 0 │ 12 │ 0.301 │ ███ │
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14. │ 0 │ 13 │ 0.273 │ ██▋ │
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15. │ 0 │ 14 │ 0.247 │ ██▍ │
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16. │ 0 │ 15 │ 0.223 │ ██▏ │
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17. │ 0 │ 16 │ 0.202 │ ██ │
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18. │ 0 │ 17 │ 0.183 │ █▊ │
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19. │ 0 │ 18 │ 0.165 │ █▋ │
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20. │ 0 │ 19 │ 0.15 │ █▍ │
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21. │ 0 │ 20 │ 0.135 │ █▎ │
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22. │ 0 │ 21 │ 0.122 │ █▏ │
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23. │ 0 │ 22 │ 0.111 │ █ │
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24. │ 0 │ 23 │ 0.1 │ █ │
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25. │ 0 │ 24 │ 0.091 │ ▉ │
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26. │ 1 │ 25 │ 1 │ ██████████ │
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27. │ 1 │ 26 │ 1 │ ██████████ │
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28. │ 1 │ 27 │ 1 │ ██████████ │
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29. │ 1 │ 28 │ 1 │ ██████████ │
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30. │ 1 │ 29 │ 1 │ ██████████ │
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31. │ 1 │ 30 │ 1 │ ██████████ │
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32. │ 1 │ 31 │ 1 │ ██████████ │
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33. │ 1 │ 32 │ 1 │ ██████████ │
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34. │ 1 │ 33 │ 1 │ ██████████ │
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35. │ 1 │ 34 │ 1 │ ██████████ │
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36. │ 1 │ 35 │ 1 │ ██████████ │
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37. │ 1 │ 36 │ 1 │ ██████████ │
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38. │ 1 │ 37 │ 1 │ ██████████ │
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39. │ 1 │ 38 │ 1 │ ██████████ │
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40. │ 1 │ 39 │ 1 │ ██████████ │
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41. │ 1 │ 40 │ 1 │ ██████████ │
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42. │ 1 │ 41 │ 1 │ ██████████ │
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43. │ 1 │ 42 │ 1 │ ██████████ │
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44. │ 1 │ 43 │ 1 │ ██████████ │
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45. │ 1 │ 44 │ 1 │ ██████████ │
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46. │ 1 │ 45 │ 1 │ ██████████ │
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47. │ 1 │ 46 │ 1 │ ██████████ │
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48. │ 1 │ 47 │ 1 │ ██████████ │
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49. │ 1 │ 48 │ 1 │ ██████████ │
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50. │ 1 │ 49 │ 1 │ ██████████ │
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└───────┴──────┴──────────────────────┴────────────┘
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``` |