Overview
The functions mentioned in this section are optimized for maximum performance and for the most part do not follow the RFC-3986 standard.
Functions which implement RFC-3986 have
RFC appended to their function name and are generally slower.RFC function variants when working with publicly registered domains that contain neither user strings nor @ symbols.
The table below details which symbols in a URL can (✔) or cannot (✗) be parsed by the respective RFC and non-RFC variants:
symbols marked
* are sub-delimiters in RFC 3986 and allowed for user info following the @ symbol.
There are two types of URL functions:
- Functions that extract parts of a URL. If the relevant part isn’t present in a URL, an empty string is returned.
- Functions that remove part of a URL. If the URL does not have anything similar, the URL remains unchanged.
The functions below are generated from the
system.functions system table.URLHierarchy
Introduced in: v1.1.0 Returns an array containing the URL, truncated at the end by the symbols/, ? and # in the path and query string. Consecutive separator characters are counted as one. The result includes the protocol and host as the first element, with progressively longer paths forming a hierarchy.
Syntax
url— The URL to process.String
Array(String)
Examples
Basic usage
Query
Response
URLPathHierarchy
Introduced in: v1.1.0 Returns an array containing the path component of the URL, truncated at the end by the symbols/, ? and #. Unlike URLHierarchy, the result does not include the protocol and host — it starts from the path. Consecutive separator characters are counted as one.
Syntax
url— The URL to process.String
Array(String)
Examples
Basic usage
Query
Response
cutFragment
Introduced in: v1.1.0 Removes the fragment identifier, including the number sign, from a URL. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
cutQueryString
Introduced in: v1.1.0 Removes the query string, including the question mark from a URL. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
cutQueryStringAndFragment
Introduced in: v1.1.0 Removes the query string and fragment identifier, including the question mark and number sign, from a URL. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomain
Introduced in: v1.1.0 Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. Syntaxurl— URL or domain string to process.String
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomainCustom
Introduced in: v21.1.0 Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. Accepts custom TLD list name. This function can be useful if you need a fresh TLD list or if you have a custom list. Configuration exampleurl— URL or domain string to process.Stringtld_list_name— Name of the custom TLD list configured in ClickHouse.const String
String
Examples
Using custom TLD list for non-standard domains
Query
Response
cutToFirstSignificantSubdomainCustomRFC
Introduced in: v22.10.0 Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. Accepts custom TLD list name. This function can be useful if you need a fresh TLD list or if you have a custom list. Similar to cutToFirstSignificantSubdomainCustom but conforms to RFC 3986. Configuration exampleurl— URL or domain string to process according to RFC 3986. -tld_list_name— Name of the custom TLD list configured in ClickHouse.
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomainCustomWithWWW
Introduced in: v21.1.0 Returns the part of the domain that includes top-level subdomains up to the first significant subdomain without stripping ‘www’. Accepts custom TLD list name. It can be useful if you need a fresh TLD list or if you have a custom list. Configuration exampleurl— URL or domain string to process. -tld_list_name— Name of the custom TLD list configured in ClickHouse.
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomainCustomWithWWWRFC
Introduced in: v22.10.0 Returns the part of the domain that includes top-level subdomains up to the first significant subdomain without strippingwww.
Accepts custom TLD list name.
It can be useful if you need a fresh TLD list or if you have a custom list.
Similar to cutToFirstSignificantSubdomainCustomWithWWW but conforms to RFC 3986.
Configuration example
url— URL or domain string to process according to RFC 3986. -tld_list_name— Name of the custom TLD list configured in ClickHouse.
www. String
Examples
RFC 3986 parsing preserving www with custom TLD list
Query
Response
cutToFirstSignificantSubdomainRFC
Introduced in: v22.10.0 Returns the part of the domain that includes top-level subdomains up to the “first significant subdomain”. Similar tocutToFirstSignificantSubdomain but conforms to RFC 3986.
Syntax
url— URL or domain string to process according to RFC 3986.String
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomainWithWWW
Introduced in: v20.12.0 Returns the part of the domain that includes top-level subdomains up to the “first significant subdomain”, without stripping ‘www.’. Similar tocutToFirstSignificantSubdomain but preserves the ‘www.’ prefix if present.
Syntax
url— URL or domain string to process.String
String
Examples
Usage example
Query
Response
cutToFirstSignificantSubdomainWithWWWRFC
Introduced in: v22.10.0 Returns the part of the domain that includes top-level subdomains up to the “first significant subdomain”, without stripping ‘www’. Similar tocutToFirstSignificantSubdomainWithWWW but conforms to RFC 3986.
Syntax
url— URL or domain string to process according to RFC 3986.
String
Examples
Usage example
Query
Response
cutURLParameter
Introduced in: v1.1.0 Removes thename parameter from a URL, if present.
This function does not encode or decode characters in parameter names, e.g. Client ID and Client%20ID are treated as different parameter names.
Syntax
url— URL.Stringname— Name of URL parameter.StringorArray(String)
name URL parameter removed. String
Examples
Usage example
Query
Response
cutWWW
Introduced in: v1.1.0 Removes the leadingwww., if present, from the URL’s domain.
Syntax
url— URL.String
www. removed from the domain. String
Examples
Usage example
Query
Response
decodeURLComponent
Introduced in: v1.1.0 Takes a URL-encoded string as input and decodes it back to its original, readable form. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
decodeURLFormComponent
Introduced in: v1.1.0 Decodes URL-encoded strings using form encoding rules (RFC-1866), where+ signs are converted to spaces and percent-encoded characters are decoded.
Syntax
url— URL.String
String
Examples
Usage example
Query
Response
domain
Introduced in: v1.1.0 Extracts the hostname from a URL. The URL can be specified with or without a protocol. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
domainRFC
Introduced in: v22.10.0 Extracts the hostname from a URL. Similar todomain, but RFC 3986 conformant.
Syntax
url— URL.String
String
Examples
Usage example
Query
Response
domainWithoutWWW
Introduced in: v1.1.0 Returns the domain of a URL without leadingwww. if present.
Syntax
url— URL.String
www.), otherwise an empty string. String
Examples
Usage example
Query
Response
domainWithoutWWWRFC
Introduced in: v1.1.0 Returns the domain without leadingwww. if present. Similar to domainWithoutWWW but conforms to RFC 3986.
Syntax
url— URL.String
www.), otherwise an empty string. String
Examples
Usage example
Query
Response
encodeURLComponent
Introduced in: v22.3.0 Takes a regular string and converts it into a URL-encoded (percent-encoded) format where special characters are replaced with their percent-encoded equivalents. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
encodeURLFormComponent
Introduced in: v22.3.0 Encodes strings using form encoding rules (RFC-1866), where spaces are converted to + signs and special characters are percent-encoded. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
extractURLParameter
Introduced in: v1.1.0 Returns the value of thename parameter in the URL, if present, otherwise an empty string is returned.
If there are multiple parameters with this name, the first occurrence is returned.
The function assumes that the parameter in the url parameter is encoded in the same way as in the name argument.
Syntax
String
Examples
Usage example
Query
Response
extractURLParameterNames
Introduced in: v1.1.0 Returns an array of name strings corresponding to the names of URL parameters. The values are not decoded. Syntaxurl— URL.String
Array(String)
Examples
Usage example
Query
Response
extractURLParameters
Introduced in: v1.1.0 Returns an array ofname=value strings corresponding to the URL parameters.
The values are not decoded.
Syntax
url— URL.String
name=value strings corresponding to the URL parameters. Array(String)
Examples
Usage example
Query
Response
firstSignificantSubdomain
Introduced in: v1.1.0 Returns the “first significant subdomain”. The first significant subdomain is a second-level domain if it is ‘com’, ‘net’, ‘org’, or ‘co’. Otherwise, it is a third-level domain. For example, firstSignificantSubdomain(‘https://news.clickhouse.com/’) = ‘clickhouse’, firstSignificantSubdomain (‘https://news.clickhouse.com.tr/’) = ‘clickhouse’. The list of “insignificant” second-level domains and other implementation details may change in the future. Syntax- None.
Query
Response
firstSignificantSubdomainCustom
Introduced in: v21.1.0 Returns the first significant subdomain of a URL using a custom TLD (Top-Level Domain) list. The custom TLD list name refers to a configuration that defines which domain suffixes should be treated as top-level domains. This is useful for non-standard TLD hierarchies. The function uses a simplified URL parsing algorithm that assumes the protocol and everything following are stripped. Syntaxurl— The URL to extract the subdomain from.Stringtld_list_name— Name of the custom TLD list from the configuration.String
String
Examples
Basic usage
Query
Response
firstSignificantSubdomainCustomRFC
Introduced in: v22.10.0 Similar tofirstSignificantSubdomainCustom but uses RFC 3986 compliant URL parsing instead of the simplified algorithm.
Syntax
url— The URL to extract the subdomain from.Stringtld_list_name— Name of the custom TLD list from the configuration.String
String
Examples
Basic usage
Query
Response
firstSignificantSubdomainRFC
Introduced in: v22.10.0 Returns the “first significant subdomain” according to RFC 1034. Syntax- None.
fragment
Introduced in: v1.1.0 Returns the fragment identifier without the initial hash symbol. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
netloc
Introduced in: v20.5.0 Extracts network locality (username:password@host:port) from a URL.
Syntax
url— URL.String
username:password@host:port from a given URL. String
Examples
Usage example
Query
Response
path
Introduced in: v1.1.0 Returns the path without query string from a URL. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
pathFull
Introduced in: v1.1.0 The same aspath, but includes the query string and fragment of the URL.
Syntax
url— URL.String
String
Examples
Usage example
Query
Response
port
Introduced in: v20.5.0 Returns the port of a URL, or thedefault_port if the URL contains no port or cannot be parsed.
Syntax
url— URL.Stringdefault_port— Optional. The default port number to be returned.0by default.UInt16
UInt16
Examples
Usage example
Query
Response
portRFC
Introduced in: v22.10.0 Returns the port ordefault_port if the URL contains no port or cannot be parsed.
Similar to port, but RFC 3986 conformant.
Syntax
url— URL.Stringdefault_port— Optional. The default port number to be returned.0by default.UInt16
UInt16
Examples
Usage example
Query
Response
protocol
Introduced in: v1.1.0 Extracts the protocol from a URL. Examples of typical returned values: http, https, ftp, mailto, tel, magnet. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
queryString
Introduced in: v1.1.0 Returns the query string of a URL without the initial question mark,# and everything after #.
Syntax
url— URL.String
String
Examples
Usage example
Query
Response
queryStringAndFragment
Introduced in: v1.1.0 Returns the query string and fragment identifier of a URL. Syntaxurl— URL.String
String
Examples
Usage example
Query
Response
topLevelDomain
Introduced in: v1.1.0 Extracts the the top-level domain from a URL.The URL can be specified with or without a protocol.
For example:
url— URL.String
String
Examples
Usage example
Query
Response
topLevelDomainRFC
Introduced in: v22.10.0 Extracts the the top-level domain from a URL. Similar totopLevelDomain, but conforms to RFC 3986.
Syntax
url— URL.String
String
Examples
Usage example
Query
Response