ClickHouse/docs/en/sql-reference/table-functions/s3.md

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---
toc_priority: 45
toc_title: s3
---
# s3 Table Function {#s3-table-function}
Provides table-like interface to select/insert files in [Amazon S3](https://aws.amazon.com/s3/). This table function is similar to [hdfs](../../sql-reference/table-functions/hdfs.md), but provides S3-specific features.
**Syntax**
``` sql
s3(path, [aws_access_key_id, aws_secret_access_key,] format, structure, [compression])
```
**Arguments**
- `path` — Bucket url with path to file. Supports following wildcards in readonly mode: `*`, `?`, `{abc,def}` and `{N..M}` where `N`, `M` — numbers, `'abc'`, `'def'` — strings. For more information see [here](../../engines/table-engines/integrations/s3.md#wildcards-in-path).
- `format` — The [format](../../interfaces/formats.md#formats) of the file.
- `structure` — Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
- `compression` — Parameter is optional. Supported values: `none`, `gzip/gz`, `brotli/br`, `xz/LZMA`, `zstd/zst`. By default, it will autodetect compression by file extension.
**Returned value**
A table with the specified structure for reading or writing data in the specified file.
**Examples**
Selecting the first two rows from the table from S3 file `https://storage.yandexcloud.net/my-test-bucket-768/data.csv`:
``` sql
SELECT *
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/data.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32')
LIMIT 2;
```
``` text
┌─column1─┬─column2─┬─column3─┐
│ 1 │ 2 │ 3 │
│ 3 │ 2 │ 1 │
└─────────┴─────────┴─────────┘
```
The similar but from file with `gzip` compression:
``` sql
SELECT *
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/data.csv.gz', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32', 'gzip')
LIMIT 2;
```
``` text
┌─column1─┬─column2─┬─column3─┐
│ 1 │ 2 │ 3 │
│ 3 │ 2 │ 1 │
└─────────┴─────────┴─────────┘
```
## Usage {#usage-examples}
Suppose that we have several files with following URIs on S3:
- 'https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_1.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_2.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_3.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/some_prefix/some_file_4.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_1.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_2.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_3.csv'
- 'https://storage.yandexcloud.net/my-test-bucket-768/another_prefix/some_file_4.csv'
Count the amount of rows in files ending with numbers from 1 to 3:
``` sql
SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/{some,another}_prefix/some_file_{1..3}.csv', 'CSV', 'name String, value UInt32')
```
``` text
┌─count()─┐
│ 18 │
└─────────┘
```
Count the total amount of rows in all files in these two directories:
``` sql
SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/{some,another}_prefix/*', 'CSV', 'name String, value UInt32')
```
``` text
┌─count()─┐
│ 24 │
└─────────┘
```
!!! warning "Warning"
If your listing of files contains number ranges with leading zeros, use the construction with braces for each digit separately or use `?`.
Count the total amount of rows in files named `file-000.csv`, `file-001.csv`, … , `file-999.csv`:
``` sql
SELECT count(*)
FROM s3('https://storage.yandexcloud.net/my-test-bucket-768/big_prefix/file-{000..999}.csv', 'CSV', 'name String, value UInt32');
```
``` text
┌─count()─┐
│ 12 │
└─────────┘
```
Insert data into file `test-data.csv.gz`:
``` sql
INSERT INTO FUNCTION s3('https://storage.yandexcloud.net/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
VALUES ('test-data', 1), ('test-data-2', 2);
```
Insert data into file `test-data.csv.gz` from existing table:
``` sql
INSERT INTO FUNCTION s3('https://storage.yandexcloud.net/my-test-bucket-768/test-data.csv.gz', 'CSV', 'name String, value UInt32', 'gzip')
SELECT name, value FROM existing_table;
```
## Partitioned Write {#partitioned-write}
If you specify `PARTITION BY` expression when inserting data into `S3` table, a separate file is created for each partition value. Splitting the data into separate files helps to improve reading operations efficiency.
**Examples**
1. Using partition ID in a key creates separate files:
```sql
INSERT INTO TABLE FUNCTION
s3('http://bucket.amazonaws.com/my_bucket/file_{_partition_id}.csv', 'CSV', 'a String, b UInt32, c UInt32')
PARTITION BY a VALUES ('x', 2, 3), ('x', 4, 5), ('y', 11, 12), ('y', 13, 14), ('z', 21, 22), ('z', 23, 24);
```
As a result, the data is written into three files: `file_x.csv`, `file_y.csv`, and `file_z.csv`.
2. Using partition ID in a bucket name creates files in different buckets:
```sql
INSERT INTO TABLE FUNCTION
s3('http://bucket.amazonaws.com/my_bucket_{_partition_id}/file.csv', 'CSV', 'a UInt32, b UInt32, c UInt32')
PARTITION BY a VALUES (1, 2, 3), (1, 4, 5), (10, 11, 12), (10, 13, 14), (20, 21, 22), (20, 23, 24);
```
As a result, the data is written into three files in different buckets: `my_bucket_1/file.csv`, `my_bucket_10/file.csv`, and `my_bucket_20/file.csv`.
**See Also**
- [S3 engine](../../engines/table-engines/integrations/s3.md)
[Original article](https://clickhouse.com/docs/en/sql-reference/table-functions/s3/) <!--hide-->