Functions for working with URLs
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.
You can generally use the non-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:
Symbol | non-RFC | RFC |
---|---|---|
' ' | ✗ | ✗ |
\t | ✗ | ✗ |
< | ✗ | ✗ |
> | ✗ | ✗ |
% | ✗ | ✔* |
{ | ✗ | ✗ |
} | ✗ | ✗ |
| | ✗ | ✗ |
\\ | ✗ | ✗ |
^ | ✗ | ✗ |
~ | ✗ | ✔* |
[ | ✗ | ✗ |
] | ✗ | ✔ |
; | ✗ | ✔* |
= | ✗ | ✔* |
& | ✗ | ✔* |
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.
cutFragment
Introduced in: v1.1
Removes the fragment identifier, including the number sign, from a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the URL with fragment identifier removed. String
Examples
Usage example
cutQueryString
Introduced in: v1.1
Removes the query string, including the question mark from a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the URL with query string removed. String
Examples
Usage example
cutQueryStringAndFragment
Introduced in: v1.1
Removes the query string and fragment identifier, including the question mark and number sign, from a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the URL with query string and fragment identifier removed. String
Examples
Usage example
cutToFirstSignificantSubdomain
Introduced in: v1.1
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain.
Syntax
Arguments
url
— URL or domain string to process.String
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain if possible, otherwise returns an empty string. String
Examples
Usage example
cutToFirstSignificantSubdomainCustom
Introduced in: v21.1
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 example
Syntax
Arguments
url
— URL or domain string to process.String
tld_list_name
— Name of the custom TLD list configured in ClickHouse.const String
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. String
Examples
Using custom TLD list for non-standard domains
cutToFirstSignificantSubdomainCustomRFC
Introduced in: v22.10
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 example
Syntax
Arguments
url
— URL or domain string to process according to RFC 3986. -tld_list_name
— Name of the custom TLD list configured in ClickHouse.
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain. String
Examples
Usage example
cutToFirstSignificantSubdomainCustomWithWWW
Introduced in: v21.1
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 example
Arguments
url
— URL or domain string to process. -tld_list_name
— Name of the custom TLD list configured in ClickHouse.
Returned value
Part of the domain that includes top-level subdomains up to the first significant subdomain without stripping 'www'. String
Examples
Usage example
cutToFirstSignificantSubdomainCustomWithWWWRFC
Introduced in: v22.10
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.
Similar to cutToFirstSignificantSubdomainCustomWithWWW but conforms to RFC 3986.
Configuration example
Arguments
url
— URL or domain string to process according to RFC 3986. -tld_list_name
— Name of the custom TLD list configured in ClickHouse.
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain without stripping www
. String
Examples
RFC 3986 parsing preserving www with custom TLD list
cutToFirstSignificantSubdomainRFC
Introduced in: v22.10
Returns the part of the domain that includes top-level subdomains up to the "first significant subdomain". Similar to cutToFirstSignificantSubdomain
but conforms to RFC 3986.
Syntax
Arguments
url
— URL or domain string to process according to RFC 3986.String
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain if possible, otherwise returns an empty string. String
Examples
Usage example
cutToFirstSignificantSubdomainWithWWW
Introduced in: v20.12
Returns the part of the domain that includes top-level subdomains up to the "first significant subdomain", without stripping 'www.'.
Similar to cutToFirstSignificantSubdomain
but preserves the 'www.' prefix if present.
Syntax
Arguments
url
— URL or domain string to process.String
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain (with www) if possible, otherwise returns an empty string. String
Examples
Usage example
cutToFirstSignificantSubdomainWithWWWRFC
Introduced in: v22.10
Returns the part of the domain that includes top-level subdomains up to the "first significant subdomain", without stripping 'www'. Similar to cutToFirstSignificantSubdomainWithWWW
but conforms to RFC 3986.
Syntax
Arguments
url
— URL or domain string to process according to RFC 3986.
Returned value
Returns the part of the domain that includes top-level subdomains up to the first significant subdomain (with 'www') if possible, otherwise returns an empty string String
Examples
Usage example
cutURLParameter
Introduced in: v1.1
Removes the name
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
Arguments
url
— URL.String
name
— Name of URL parameter.String
orArray(String)
Returned value
URL with name
URL parameter removed. String
Examples
Usage example
cutWWW
Introduced in: v1.1
Removes the leading www.
, if present, from the URL's domain.
Syntax
Arguments
url
— URL.String
Returned value
Returns the URL with leading www.
removed from the domain. String
Examples
Usage example
decodeURLComponent
Introduced in: v1.1
Takes a URL-encoded string as input and decodes it back to its original, readable form.
Syntax
Arguments
url
— URL.String
Returned value
Returns the decoded URL. String
Examples
Usage example
decodeURLFormComponent
Introduced in: v1.1
Decodes URL-encoded strings using form encoding rules (RFC-1866), where +
signs are converted to spaces and percent-encoded characters are decoded.
Syntax
Arguments
url
— URL.String
Returned value
Returns the decoded URL. String
Examples
Usage example
domain
Introduced in: v1.1
Extracts the hostname from a URL.
The URL can be specified with or without a protocol.
Syntax
Arguments
url
— URL.String
Returned value
Returns the host name if the input string can be parsed as a URL, otherwise an empty string. String
Examples
Usage example
domainRFC
Introduced in: v22.10
Extracts the hostname from a URL.
Similar to domain
, but RFC 3986 conformant.
Syntax
Arguments
url
— URL.String
Returned value
Returns the host name if the input string can be parsed as a URL, otherwise an empty string. String
Examples
Usage example
domainWithoutWWW
Introduced in: v1.1
Returns the domain of a URL without leading www.
if present.
Syntax
Arguments
url
— URL.String
Returned value
Returns the domain name if the input string can be parsed as a URL (without leading www.
), otherwise an empty string. String
Examples
Usage example
domainWithoutWWWRFC
Introduced in: v1.1
Returns the domain without leading www.
if present. Similar to domainWithoutWWW
but conforms to RFC 3986.
Syntax
Arguments
url
— URL.String
Returned value
Returns the domain name if the input string can be parsed as a URL (without leading www.
), otherwise an empty string. String
Examples
Usage example
encodeURLComponent
Introduced in: v22.3
Takes a regular string and converts it into a URL-encoded (percent-encoded) format where special characters are replaced with their percent-encoded equivalents.
Syntax
Arguments
url
— URL.String
Returned value
Returns the encoded URL. String
Examples
Usage example
encodeURLFormComponent
Introduced in: v22.3
Encodes strings using form encoding rules (RFC-1866), where spaces are converted to + signs and special characters are percent-encoded.
Syntax
Arguments
url
— URL.String
Returned value
Returns the encoded URL. String
Examples
Usage example
extractURLParameter
Introduced in: v1.1
Returns the value of the name
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
Arguments
Returned value
Returns the value of the URL parameter with the specified name. String
Examples
Usage example
extractURLParameterNames
Introduced in: v1.1
Returns an array of name strings corresponding to the names of URL parameters. The values are not decoded.
Syntax
Arguments
url
— URL.String
Returned value
Returns an array of name strings corresponding to the names of URL parameters. Array(String)
Examples
Usage example
extractURLParameters
Introduced in: v1.1
Returns an array of name=value
strings corresponding to the URL parameters.
The values are not decoded.
Syntax
Arguments
url
— URL.String
Returned value
Returns an array of name=value
strings corresponding to the URL parameters. Array(String)
Examples
Usage example
firstSignificantSubdomain
Introduced in: v
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
Arguments
- None. Returned value
Examples
firstSignificantSubdomain
firstSignificantSubdomainRFC
Introduced in: v
Returns the "first significant subdomain" according to RFC 1034.
Syntax
Arguments
- None. Returned value
Examples
fragment
Introduced in: v1.1
Returns the fragment identifier without the initial hash symbol.
Syntax
Arguments
url
— URL.String
Returned value
Returns the fragment identifier without the initial hash symbol. String
Examples
Usage example
netloc
Introduced in: v20.5
Extracts network locality (username:password@host:port
) from a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns username:password@host:port
from a given URL. String
Examples
Usage example
path
Introduced in: v1.1
Returns the path without query string from a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the path of the URL without query string. String
Examples
Usage example
pathFull
Introduced in: v1.1
The same as path
, but includes the query string and fragment of the URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the path of the URL including query string and fragment. String
Examples
Usage example
port
Introduced in: v20.5
Returns the port of a URL, or the default_port
if the URL contains no port or cannot be parsed.
Syntax
Arguments
url
— URL.String
default_port
— Optional. The default port number to be returned.0
by default.UInt16
Returned value
Returns the port of the URL, or the default port if there is no port in the URL or in case of a validation error. UInt16
Examples
Usage example
portRFC
Introduced in: v22.10
Returns the port or default_port
if the URL contains no port or cannot be parsed.
Similar to port
, but RFC 3986 conformant.
Syntax
Arguments
url
— URL.String
default_port
— Optional. The default port number to be returned.0
by default.UInt16
Returned value
Returns the port or the default port if there is no port in the URL or in case of a validation error. UInt16
Examples
Usage example
protocol
Introduced in: v1.1
Extracts the protocol from a URL.
Examples of typical returned values: http, https, ftp, mailto, tel, magnet.
Syntax
Arguments
url
— URL.String
Returned value
Returns the protocol of the URL, or an empty string if it cannot be determined. String
Examples
Usage example
queryString
Introduced in: v1.1
Returns the query string of a URL without the initial question mark, #
and everything after #
.
Syntax
Arguments
url
— URL.String
Returned value
Returns the query string of the URL without the initial question mark and fragment. String
Examples
Usage example
queryStringAndFragment
Introduced in: v1.1
Returns the query string and fragment identifier of a URL.
Syntax
Arguments
url
— URL.String
Returned value
Returns the query string and fragment identifier of the URL. String
Examples
Usage example
topLevelDomain
Introduced in: v1.1
Extracts the the top-level domain from a URL.
The URL can be specified with or without a protocol. For example:
Syntax
Arguments
url
— URL.String
Returned value
Returns the domain name if the input string can be parsed as a URL. Otherwise, an empty string. String
Examples
Usage example
topLevelDomainRFC
Introduced in: v22.10
Extracts the the top-level domain from a URL.
Similar to topLevelDomain
, but conforms to RFC 3986.
Syntax
Arguments
url
— URL.String
Returned value
Domain name if the input string can be parsed as a URL. Otherwise, an empty string. String
Examples
Usage example