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105 lines
5.4 KiB
Markdown
105 lines
5.4 KiB
Markdown
---
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slug: /en/sql-reference/aggregate-functions/reference/exponentialTimeDecayedAvg
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sidebar_position: 133
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title: exponentialTimeDecayedAvg
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---
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## exponentialTimeDecayedAvg
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Returns the exponentially smoothed weighted moving average of values of a time series at point `t` in time.
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**Syntax**
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```sql
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exponentialTimeDecayedAvg(x)(v, t)
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```
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**Arguments**
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- `v` — 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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- `t` — Time. [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 an exponentially smoothed weighted moving average at index `t` in time. [Float64](../../data-types/float.md).
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**Examples**
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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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exponentialTimeDecayedAvg(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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Response:
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```sql
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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 │ 0.475 │ ████▊ │
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3. │ 0 │ 2 │ 0.301 │ ███ │
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4. │ 0 │ 3 │ 0.214 │ ██▏ │
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5. │ 0 │ 4 │ 0.162 │ █▌ │
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6. │ 0 │ 5 │ 0.128 │ █▎ │
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7. │ 0 │ 6 │ 0.104 │ █ │
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8. │ 0 │ 7 │ 0.086 │ ▊ │
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9. │ 0 │ 8 │ 0.072 │ ▋ │
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0. │ 0 │ 9 │ 0.061 │ ▌ │
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1. │ 0 │ 10 │ 0.052 │ ▌ │
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2. │ 0 │ 11 │ 0.045 │ ▍ │
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3. │ 0 │ 12 │ 0.039 │ ▍ │
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4. │ 0 │ 13 │ 0.034 │ ▎ │
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5. │ 0 │ 14 │ 0.03 │ ▎ │
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6. │ 0 │ 15 │ 0.027 │ ▎ │
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7. │ 0 │ 16 │ 0.024 │ ▏ │
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8. │ 0 │ 17 │ 0.021 │ ▏ │
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9. │ 0 │ 18 │ 0.018 │ ▏ │
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0. │ 0 │ 19 │ 0.016 │ ▏ │
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1. │ 0 │ 20 │ 0.015 │ ▏ │
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2. │ 0 │ 21 │ 0.013 │ ▏ │
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3. │ 0 │ 22 │ 0.012 │ │
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4. │ 0 │ 23 │ 0.01 │ │
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5. │ 0 │ 24 │ 0.009 │ │
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6. │ 1 │ 25 │ 0.111 │ █ │
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7. │ 1 │ 26 │ 0.202 │ ██ │
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8. │ 1 │ 27 │ 0.283 │ ██▊ │
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9. │ 1 │ 28 │ 0.355 │ ███▌ │
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0. │ 1 │ 29 │ 0.42 │ ████▏ │
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1. │ 1 │ 30 │ 0.477 │ ████▊ │
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2. │ 1 │ 31 │ 0.529 │ █████▎ │
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3. │ 1 │ 32 │ 0.576 │ █████▊ │
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4. │ 1 │ 33 │ 0.618 │ ██████▏ │
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5. │ 1 │ 34 │ 0.655 │ ██████▌ │
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6. │ 1 │ 35 │ 0.689 │ ██████▉ │
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7. │ 1 │ 36 │ 0.719 │ ███████▏ │
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8. │ 1 │ 37 │ 0.747 │ ███████▍ │
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9. │ 1 │ 38 │ 0.771 │ ███████▋ │
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0. │ 1 │ 39 │ 0.793 │ ███████▉ │
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1. │ 1 │ 40 │ 0.813 │ ████████▏ │
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2. │ 1 │ 41 │ 0.831 │ ████████▎ │
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3. │ 1 │ 42 │ 0.848 │ ████████▍ │
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4. │ 1 │ 43 │ 0.862 │ ████████▌ │
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5. │ 1 │ 44 │ 0.876 │ ████████▊ │
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6. │ 1 │ 45 │ 0.888 │ ████████▉ │
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7. │ 1 │ 46 │ 0.898 │ ████████▉ │
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8. │ 1 │ 47 │ 0.908 │ █████████ │
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9. │ 1 │ 48 │ 0.917 │ █████████▏ │
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0. │ 1 │ 49 │ 0.925 │ █████████▏ │
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└───────┴──────┴──────────────────────┴────────────┘
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``` |