ClickHouse/docs/en/sql-reference/table-functions/generate.md

42 lines
1.9 KiB
Markdown
Raw Normal View History

2020-04-03 13:23:32 +00:00
---
toc_priority: 47
toc_title: generateRandom
---
2020-03-20 10:10:48 +00:00
# generateRandom {#generaterandom}
2020-02-04 10:59:26 +00:00
Generates random data with given schema.
Allows to populate test tables with data.
2020-02-04 12:25:09 +00:00
Supports all data types that can be stored in table except `LowCardinality` and `AggregateFunction`.
2020-02-04 10:59:26 +00:00
2020-03-20 10:10:48 +00:00
``` sql
generateRandom('name TypeName[, name TypeName]...', [, 'random_seed'[, 'max_string_length'[, 'max_array_length']]])
2020-02-04 10:59:26 +00:00
```
2021-02-15 21:38:32 +00:00
**Arguments**
2020-02-04 10:59:26 +00:00
- `name` — Name of corresponding column.
- `TypeName` — Type of corresponding column.
- `max_array_length` — Maximum array length for all generated arrays. Defaults to `10`.
- `max_string_length` — Maximum string length for all generated strings. Defaults to `10`.
- `random_seed` — Specify random seed manually to produce stable results. If NULL — seed is randomly generated.
2020-02-04 10:59:26 +00:00
**Returned Value**
A table object with requested schema.
2020-03-20 10:10:48 +00:00
## Usage Example {#usage-example}
2020-02-04 10:59:26 +00:00
2020-03-20 10:10:48 +00:00
``` sql
2020-04-24 21:47:27 +00:00
SELECT * FROM generateRandom('a Array(Int8), d Decimal32(4), c Tuple(DateTime64(3), UUID)', 1, 10, 2) LIMIT 3;
2020-02-04 10:59:26 +00:00
```
2020-03-20 10:10:48 +00:00
``` text
2020-02-04 10:59:26 +00:00
┌─a────────┬────────────d─┬─c──────────────────────────────────────────────────────────────────┐
│ [77] │ -124167.6723 │ ('2061-04-17 21:59:44.573','3f72f405-ec3e-13c8-44ca-66ef335f7835') │
│ [32,110] │ -141397.7312 │ ('1979-02-09 03:43:48.526','982486d1-5a5d-a308-e525-7bd8b80ffa73') │
│ [68] │ -67417.0770 │ ('2080-03-12 14:17:31.269','110425e5-413f-10a6-05ba-fa6b3e929f15') │
└──────────┴──────────────┴────────────────────────────────────────────────────────────────────┘
```