ClickHouse/docs/en/sql-reference/table-functions/file.md
2022-06-02 04:55:18 -06:00

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---
sidebar_position: 37
sidebar_label: file
---
# file
Creates a table from a file. This table function is similar to [url](../../sql-reference/table-functions/url.md) and [hdfs](../../sql-reference/table-functions/hdfs.md) ones.
`file` function can be used in `SELECT` and `INSERT` queries on data in [File](../../engines/table-engines/special/file.md) tables.
**Syntax**
``` sql
file(path, format, structure)
```
**Parameters**
- `path` — The relative path to the file from [user_files_path](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-user_files_path). Path to file support following globs in read-only mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc', 'def'` — strings.
- `format` — The [format](../../interfaces/formats.md#formats) of the file.
- `structure` — Structure of the table. Format: `'column1_name column1_type, column2_name column2_type, ...'`.
**Returned value**
A table with the specified structure for reading or writing data in the specified file.
**Examples**
Setting `user_files_path` and the contents of the file `test.csv`:
``` bash
$ grep user_files_path /etc/clickhouse-server/config.xml
<user_files_path>/var/lib/clickhouse/user_files/</user_files_path>
$ cat /var/lib/clickhouse/user_files/test.csv
1,2,3
3,2,1
78,43,45
```
Getting data from a table in `test.csv` and selecting the first two rows from it:
``` sql
SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') LIMIT 2;
```
``` text
┌─column1─┬─column2─┬─column3─┐
│ 1 │ 2 │ 3 │
│ 3 │ 2 │ 1 │
└─────────┴─────────┴─────────┘
```
Getting the first 10 lines of a table that contains 3 columns of [UInt32](../../sql-reference/data-types/int-uint.md) type from a CSV file:
``` sql
SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') LIMIT 10;
```
Inserting data from a file into a table:
``` sql
INSERT INTO FUNCTION file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') VALUES (1, 2, 3), (3, 2, 1);
SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32');
```
``` text
┌─column1─┬─column2─┬─column3─┐
│ 1 │ 2 │ 3 │
│ 3 │ 2 │ 1 │
└─────────┴─────────┴─────────┘
```
## Globs in Path
Multiple path components can have globs. For being processed file must exist and match to the whole path pattern (not only suffix or prefix).
- `*` — Substitutes any number of any characters except `/` including empty string.
- `?` — Substitutes any single character.
- `{some_string,another_string,yet_another_one}` — Substitutes any of strings `'some_string', 'another_string', 'yet_another_one'`.
- `{N..M}` — Substitutes any number in range from N to M including both borders.
Constructions with `{}` are similar to the [remote](remote.md) table function.
**Example**
Suppose we have several files with the following relative paths:
- 'some_dir/some_file_1'
- 'some_dir/some_file_2'
- 'some_dir/some_file_3'
- 'another_dir/some_file_1'
- 'another_dir/some_file_2'
- 'another_dir/some_file_3'
Query the number of rows in these files:
``` sql
SELECT count(*) FROM file('{some,another}_dir/some_file_{1..3}', 'TSV', 'name String, value UInt32');
```
Query the number of rows in all files of these two directories:
``` sql
SELECT count(*) FROM file('{some,another}_dir/*', 'TSV', 'name String, value UInt32');
```
:::warning
If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
:::
**Example**
Query the data from files named `file000`, `file001`, … , `file999`:
``` sql
SELECT count(*) FROM file('big_dir/file{0..9}{0..9}{0..9}', 'CSV', 'name String, value UInt32');
```
## Virtual Columns
- `_path` — Path to the file.
- `_file` — Name of the file.
**See Also**
- [Virtual columns](../../engines/table-engines/index.md#table_engines-virtual_columns)
[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/file/) <!--hide-->