2020-03-06 02:19:55 +00:00
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# generateRandom
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2020-02-04 10:59:26 +00:00
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Generates random data with given schema.
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Allows to populate test tables with data.
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2020-02-04 12:25:09 +00:00
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Supports all data types that can be stored in table except `LowCardinality` and `AggregateFunction`.
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2020-02-04 10:59:26 +00:00
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```sql
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2020-03-07 20:35:55 +00:00
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generateRandom('name TypeName[, name TypeName]...', [, 'random_seed'[, 'max_string_length'[, 'max_array_length']]]);
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2020-02-04 10:59:26 +00:00
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```
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**Parameters**
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- `name` — Name of corresponding column.
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- `TypeName` — Type of corresponding column.
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- `limit` — Number of rows to generate.
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- `max_array_length` — Maximum array length for all generated arrays. Defaults to `10`.
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- `max_string_length` — Maximum string length for all generated strings. Defaults to `10`.
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2020-03-07 20:35:55 +00:00
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- `random_seed` — Specify random seed manually to produce stable results. If NULL — seed is randomly generated.
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2020-02-04 10:59:26 +00:00
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**Returned Value**
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A table object with requested schema.
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## Usage Example
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```sql
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2020-03-07 20:35:55 +00:00
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SELECT * FROM generateRandom('a Array(Int8), d Decimal32(4), c Tuple(DateTime64(3), UUID)', 1, 10, 2);
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```
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```text
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┌─a────────┬────────────d─┬─c──────────────────────────────────────────────────────────────────┐
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│ [77] │ -124167.6723 │ ('2061-04-17 21:59:44.573','3f72f405-ec3e-13c8-44ca-66ef335f7835') │
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│ [32,110] │ -141397.7312 │ ('1979-02-09 03:43:48.526','982486d1-5a5d-a308-e525-7bd8b80ffa73') │
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│ [68] │ -67417.0770 │ ('2080-03-12 14:17:31.269','110425e5-413f-10a6-05ba-fa6b3e929f15') │
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└──────────┴──────────────┴────────────────────────────────────────────────────────────────────┘
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```
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[Original article](https://clickhouse.tech/docs/en/query_language/table_functions/generate/) <!--hide-->
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