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* Update of english version of descriprion of the table function `file`. * New syntax for ReplacingMergeTree. Some improvements in text. * Significantly change article about SummingMergeTree. Article is restructured, text is changed in many places of the document. New syntax for table creation is described. * Descriptions of AggregateFunction and AggregatingMergeTree are updated. Russian version. * New syntax for new syntax of CREATE TABLE * Added english docs on Aggregating, Replacing and SummingMergeTree. * CollapsingMergeTree docs. English version. * 1. Update of CollapsingMergeTree. 2. Minor changes in markup * Update aggregatefunction.md * Update aggregatefunction.md * Update aggregatefunction.md * Update aggregatingmergetree.md * GraphiteMergeTree docs update. New syntax for creation of Replicated* tables. Minor changes in *MergeTree tables creation syntax. * Markup fix * Markup and language fixes * Clarification in the CollapsingMergeTree article
56 lines
1.5 KiB
Markdown
56 lines
1.5 KiB
Markdown
<a name="table_functions-file"></a>
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# file
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Creates a table from a file.
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```
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file(path, format, structure)
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```
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**Input parameters**
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- `path` — The relative path to the file from [user_files_path](../../operations/server_settings/settings.md#user_files_path).
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- `format` — The [format](../../interfaces/formats.md#formats) of the file.
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- `structure` — Structure of the table. Format `'colunmn1_name column1_ype, column2_name column2_type, ...'`.
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**Returned value**
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A table with the specified structure for reading or writing data in the specified file.
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**Example**
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Setting `user_files_path` and the contents of the file `test.csv`:
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```bash
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$ grep user_files_path /etc/clickhouse-server/config.xml
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<user_files_path>/var/lib/clickhouse/user_files/</user_files_path>
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$ cat /var/lib/clickhouse/user_files/test.csv
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1,2,3
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3,2,1
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78,43,45
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```
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Table from`test.csv` and selection of the first two rows from it:
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```sql
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SELECT *
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FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32')
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LIMIT 2
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```
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```
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┌─column1─┬─column2─┬─column3─┐
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│ 1 │ 2 │ 3 │
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│ 3 │ 2 │ 1 │
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└─────────┴─────────┴─────────┘
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```
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``` sql
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-- getting the first 10 lines of a table that contains 3 columns of UInt32 type from a CSV file
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SELECT * FROM file('test.csv', 'CSV', 'column1 UInt32, column2 UInt32, column3 UInt32') LIMIT 10
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```
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[Original article](https://clickhouse.yandex/docs/en/query_language/table_functions/file/) <!--hide-->
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