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

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41	url

url

url function creates a table from the URL with given format and structure.

url function may be used in SELECT and INSERT queries on data in URL tables.

Syntax

url(URL, format, structure)

Parameters

• URL — HTTP or HTTPS server address, which can accept GET or POST requests (for SELECT or INSERT queries correspondingly). Type: String.
• format — Format of the data. Type: String.
• structure — Table structure in 'UserID UInt64, Name String' format. Determines column names and types. Type: String.

Returned value

A table with the specified format and structure and with data from the defined URL.

Patterns in URL

Patterns in curly brackets { } are used to generate a set of shards or specify failover addresses. Multiple patterns are allowed in a single URL. The following pattern types are supported.

• {a,b} - Any number of variants separated by a comma. The pattern is replaced with a in the first shard address and it is replaced with b in the second shard address and so on. For instance, example0{1,2}-1 generates example01-1 and example02-1.
• {n..m} - A range of numbers. This pattern generates shard addresses with incrementing indices from n to m. example0{1..2}-1 generates example01-1 and example02-1.
• {0n..0m} - A range of numbers with leading zeroes. This modification preserves leading zeroes in indices. The pattern example{01..03}-1 generates example01-1, example02-1 and example03-1.
• {a|b} - Any number of variants separated by a |. The pattern specifies a failover: the URL address with b is used if the address with a is not available. The pattern example01-{1|2} generates example01-1. If it is not available then example01-2 is used.

Examples

Getting the first 3 lines of a table that contains columns of String and UInt32 type from HTTP-server which answers in CSV format.

SELECT * FROM url('http://127.0.0.1:12345/', CSV, 'column1 String, column2 UInt32') LIMIT 3;

Inserting data from a URL into a table:

CREATE TABLE test_table (column1 String, column2 UInt32) ENGINE=Memory;
INSERT INTO FUNCTION url('http://127.0.0.1:8123/?query=INSERT+INTO+test_table+FORMAT+CSV', 'CSV', 'column1 String, column2 UInt32') VALUES ('http interface', 42);
SELECT * FROM test_table;