[Interprets](/docs/en/sql-reference/functions/type-conversion-functions.md/#type_conversion_functions-reinterpretAsString) all the input parameters as strings and calculates the [MD5](https://en.wikipedia.org/wiki/MD5) hash value for each of them. Then combines hashes, takes the first 8 bytes of the hash of the resulting string, and interprets them as `UInt64` in big-endian byte order.
The function takes a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
The function [interprets](/docs/en/sql-reference/functions/type-conversion-functions.md/#type_conversion_functions-reinterpretAsString) all the input parameters as strings and calculates the hash value for each of them. It then combines the hashes by the following algorithm:
Note that the calculated hash values may be equal for the same input values of different argument types. This affects for example integer types of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data.
This is a fast non-cryptographic hash function. It uses the CityHash algorithm for string parameters and implementation-specific fast non-cryptographic hash function for parameters with other data types. The function uses the CityHash combinator to get the final results.
Note that Google changed the algorithm of CityHash after it has been added to ClickHouse. In other words, ClickHouse's cityHash64 and Google's upstream CityHash now produce different results. ClickHouse cityHash64 corresponds to CityHash v1.0.2.
The function takes a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
Calculates SHA-1, SHA-224, SHA-256, SHA-512 hash from a string and returns the resulting set of bytes as [FixedString](/docs/en/sql-reference/data-types/fixedstring.md).
The function works fairly slowly (SHA-1 processes about 5 million short strings per second per processor core, while SHA-224 and SHA-256 process about 2.2 million).
Even in these cases, we recommend applying the function offline and pre-calculating values when inserting them into the table, instead of applying it in `SELECT` queries.
- SHA hash as a hex-unencoded FixedString. SHA-1 returns as FixedString(20), SHA-224 as FixedString(28), SHA-256 — FixedString(32), SHA-512 — FixedString(64).
This cryptographic hash-function is integrated into ClickHouse with BLAKE3 Rust library. The function is rather fast and shows approximately two times faster performance compared to SHA-2, while generating hashes of the same length as SHA-256.
A fast, decent-quality non-cryptographic hash function for a string obtained from a URL using some type of normalization.
`URLHash(s)`– Calculates a hash from a string without one of the trailing symbols `/`,`?` or `#` at the end, if present.
`URLHash(s, N)`– Calculates a hash from a string up to the N level in the URL hierarchy, without one of the trailing symbols `/`,`?` or `#` at the end, if present.
Produces a 64-bit [FarmHash](https://github.com/google/farmhash) or Fingerprint value. `farmFingerprint64` is preferred for a stable and portable value.
These functions use the `Fingerprint64` and `Hash64` methods respectively from all [available methods](https://github.com/google/farmhash/blob/master/src/farmhash.h).
The function takes a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
This hash function is neither fast nor having a good quality. The only reason to use it is when this algorithm is already used in another system and you have to calculate exactly the same result.
Note that Java only support calculating signed integers hash, so if you want to calculate unsigned integers hash you must cast it to proper signed ClickHouse types.
Calculates [JavaHash](http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/478a4add975b/src/share/classes/java/lang/String.java#l1452) from a string, assuming it contains bytes representing a string in UTF-16LE encoding.
This is just [JavaHash](#hash_functions-javahash) with zeroed out sign bit. This function is used in [Apache Hive](https://en.wikipedia.org/wiki/Apache_Hive) for versions before 3.0. This hash function is neither fast nor having a good quality. The only reason to use it is when this algorithm is already used in another system and you have to calculate exactly the same result.
The function takes a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
Both functions take a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
Calculates a 64-bit [MurmurHash2](https://github.com/aappleby/smhasher) hash value using the same hash seed as [gcc](https://github.com/gcc-mirror/gcc/blob/41d6b10e96a1de98e90a7c0378437c3255814b16/libstdc%2B%2B-v3/include/bits/functional_hash.h#L191). It is portable between Clang and GCC builds.
Calculates a 32-bit [MurmurHash2](https://github.com/aappleby/smhasher) hash value using the same hash seed as [Kafka](https://github.com/apache/kafka/blob/461c5cfe056db0951d9b74f5adc45973670404d7/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L482) and without the highest bit to be compatible with [Default Partitioner](https://github.com/apache/kafka/blob/139f7709bd3f5926901a21e55043388728ccca78/clients/src/main/java/org/apache/kafka/clients/producer/internals/BuiltInPartitioner.java#L328).
Both functions take a variable number of input parameters. Arguments can be any of the [supported data types](/docs/en/sql-reference/data-types/index.md). For some data types calculated value of hash function may be the same for the same values even if types of arguments differ (integers of different size, named and unnamed `Tuple` with the same data, `Map` and the corresponding `Array(Tuple(key, value))` type with the same data).
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleSimHash('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleSimHashCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleSimHashUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
Can be used for detection of semi-duplicate strings with [bitHammingDistance](/docs/en/sql-reference/functions/bit-functions.md/#bithammingdistance). The smaller is the [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) of the calculated `simhashes` of two strings, the more likely these strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleSimHashCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Hash;
Splits a ASCII string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a ASCII string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a UTF-8 string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a UTF-8 string into n-grams of `ngramsize` symbols and calculates hash values for each n-gram. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHash](#ngramminhash) function with the same input. Is case sensitive.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a ASCII string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashCaseInsensitive](#ngramminhashcaseinsensitive) function with the same input. Is case insensitive.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashUTF8](#ngramminhashutf8) function with the same input. Is case sensitive.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a UTF-8 string into n-grams of `ngramsize` symbols and returns the n-grams with minimum and maximum hashes, calculated by the [ngramMinHashCaseInsensitiveUTF8](#ngramminhashcaseinsensitiveutf8) function with the same input. Is case insensitive.
-`ngramsize` — The size of an n-gram. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
Splits a ASCII string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHash('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
Splits a ASCII string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
Splits a UTF-8 string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case sensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
Splits a UTF-8 string into parts (shingles) of `shinglesize` words and calculates hash values for each word shingle. Uses `hashnum` minimum hashes to calculate the minimum hash and `hashnum` maximum hashes to calculate the maximum hash. Returns a tuple with these hashes. Is case insensitive.
Can be used for detection of semi-duplicate strings with [tupleHammingDistance](/docs/en/sql-reference/functions/tuple-functions.md/#tuplehammingdistance). For two strings: if one of the returned hashes is the same for both strings, we think that those strings are the same.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).') AS Tuple;
Splits a ASCII string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordshingleMinHash](#wordshingleminhash) function with the same input. Is case sensitive.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashArg('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
Splits a ASCII string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashCaseInsensitive](#wordshingleminhashcaseinsensitive) function with the same input. Is case insensitive.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashArgCaseInsensitive('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
Splits a UTF-8 string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashUTF8](#wordshingleminhashutf8) function with the same input. Is case sensitive.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashArgUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;
Splits a UTF-8 string into parts (shingles) of `shinglesize` words each and returns the shingles with minimum and maximum word hashes, calculated by the [wordShingleMinHashCaseInsensitiveUTF8](#wordshingleminhashcaseinsensitiveutf8) function with the same input. Is case insensitive.
-`shinglesize` — The size of a word shingle. Optional. Possible values: any number from `1` to `25`. Default value: `3`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
-`hashnum` — The number of minimum and maximum hashes used to calculate the result. Optional. Possible values: any number from `1` to `25`. Default value: `6`. [UInt8](/docs/en/sql-reference/data-types/int-uint.md).
SELECT wordShingleMinHashArgCaseInsensitiveUTF8('ClickHouse® is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP).', 1, 3) AS Tuple;