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Merge pull request #6786 from den-crane/patch-3

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Doc change. Example of max_block_size impact on runningDifference.
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alexey-milovidov 2019-09-03 02:24:59 +03:00 committed by GitHub
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27
docs/en/query_language/functions/other_functions.md
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@ -394,6 +394,33 @@ FROM
└─────────┴─────────────────────┴───────┘
```
Please note - block size affects the result. With each new block, the `runningDifference` state is reset.
``` sql
SELECT
number,
runningDifference(number + 1) AS diff
FROM numbers(100000)
WHERE diff != 1
┌─number─┬─diff─┐
│ 0 │ 0 │
└────────┴──────┘
┌─number─┬─diff─┐
│ 65536 │ 0 │
└────────┴──────┘
set max_block_size=100000 // default value is 65536!
SELECT
number,
runningDifference(number + 1) AS diff
FROM numbers(100000)
WHERE diff != 1
┌─number─┬─diff─┐
│ 0 │ 0 │
└────────┴──────┘
```
## runningDifferenceStartingWithFirstValue
Same as for [runningDifference](./other_functions.md#other_functions-runningdifference), the difference is the value of the first row, returned the value of the first row, and each subsequent row returns the difference from the previous row.

33
docs/ru/query_language/functions/other_functions.md
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@ -369,6 +369,39 @@ FROM
└─────────┴─────────────────────┴───────┘
```
Обратите внимание — размер блока влияет на результат. С каждым новым блоком состояние `runningDifference` сбрасывается.
``` sql
SELECT
number,
runningDifference(number + 1) AS diff
FROM numbers(100000)
WHERE diff != 1
┌─number─┬─diff─┐
│ 0 │ 0 │
└────────┴──────┘
┌─number─┬─diff─┐
│ 65536 │ 0 │
└────────┴──────┘
set max_block_size=100000 // по умолчанию 65536!
SELECT
number,
runningDifference(number + 1) AS diff
FROM numbers(100000)
WHERE diff != 1
┌─number─┬─diff─┐
│ 0 │ 0 │
└────────┴──────┘
```
## runningDifferenceStartingWithFirstValue
То же, что и [runningDifference] (./other_functions.md # other_functions-runningdifference), но в первой строке возвращается значение первой строки, а не ноль.
## MACNumToString(num)
Принимает число типа UInt64. Интерпретирует его, как MAC-адрес в big endian. Возвращает строку, содержащую соответствующий MAC-адрес в формате AA:BB:CC:DD:EE:FF (числа в шестнадцатеричной форме через двоеточие).