The DuckDB chsql community extension implements popular ClickHouse SQL syntax macros and functions,
making it easier for users to transition between the two database systems ⭐ designed for Quackpipe
chsql is distributed as a DuckDB Community Extension and can be installed using SQL:
INSTALL chsql FROM community;
LOAD chsql;If you previously installed the chsql extension, upgrade using the FORCE command
FORCE INSTALL chsql FROM community;
LOAD chsql;Once installed, the macro functions provided by the extension can be used just like built-in functions.
Here's a random example out of 100s using the IPv4StringToNum and IPv4NumToString functions:
D INSTALL chsql FROM community;
D LOAD chsql;
D SELECT IPv4StringToNum('127.0.0.1'), IPv4NumToString(2130706433);
┌──────────────────────────────┬─────────────────────────────┐
│ ipv4stringtonum('127.0.0.1') │ ipv4numtostring(2130706433) │
│ int32 │ varchar │
├──────────────────────────────┼─────────────────────────────┤
│ 2130706433 │ 127.0.0.1 │
└──────────────────────────────┴─────────────────────────────┘The built-in ch_scan function can be used to query remote ClickHouse servers using the HTTP/s API
D SELECT * FROM ch_scan("SELECT number * 2 FROM numbers(10)", "https://play.clickhouse.com");👉 The list of supported aliases is available on the dedicated extension page
👉 The combined list of supported functions can be obtained using an SQL Join
Why is the DuckDB + chsql combo fun and useful
✔ DuckDB SQL is awesome and full of great functions.
✔ ClickHouse SQL is awesome and full of great functions.
✔ The DuckDB library is ~51M and modular. Can LOAD extensions.
❌ The ClickHouse monolith is ~551M and growing. No extensions.
✔ DuckDB is open source and protected by a no-profit foundation.
❌ ClickHouse is open core and controlled by for-profit corporation.
✔ DuckDB embedded is fast, mature and elegantly integrated in many languages.
❌ chdb is still experimental, unstable and currently only supports Python.
| function | fun_type | description | comment | example |
|---|---|---|---|---|
| IPv4NumToString | macro | Cast IPv4 address from numeric to string format | SELECT IPv4NumToString(2130706433); | |
| IPv4StringToNum | macro | Cast IPv4 address from string to numeric format | SELECT IPv4StringToNum('127.0.0.1'); | |
| arrayExists | macro | Check if any element of the array satisfies the condition | SELECT arrayExists(x -> x = 1, [1, 2, 3]); | |
| arrayJoin | macro | Unroll an array into multiple rows | SELECT arrayJoin([1, 2, 3]); | |
| arrayMap | macro | Applies a function to each element of an array | SELECT arrayMap(x -> x + 1, [1, 2, 3]); | |
| bitCount | macro | Counts the number of set bits in an integer | SELECT bitCount(15); | |
| ch_scan | table_macro | Query a remote ClickHouse server using HTTP/s API | Returns the query results | SELECT * FROM ch_scan('SELECT version()','https://play.clickhouse.com', format := 'parquet'); |
| domain | macro | Extracts the domain from a URL | SELECT domain('https://clickhouse.com/docs'); | |
| empty | macro | Check if a string is empty | SELECT empty(''); | |
| extractAllGroups | macro | Extracts all matching groups from a string using a regular expression | SELECT extractAllGroups('(\d+)', 'abc123'); | |
| formatDateTime | macro | Formats a DateTime value into a string | SELECT formatDateTime(now(), '%Y-%m-%d'); | |
| generateUUIDv4 | macro | Generate a UUID v4 value | SELECT generateUUIDv4(); | |
| ifNull | macro | Returns the first argument if not NULL, otherwise the second | SELECT ifNull(NULL, 'default'); | |
| intDiv | macro | Performs integer division | SELECT intDiv(10, 3); | |
| intDivOZero | macro | Performs integer division but returns zero instead of throwing an error for division by zero | SELECT intDivOZero(10, 0); | |
| intDivOrNull | macro | Performs integer division but returns NULL instead of throwing an error for division by zero | SELECT intDivOrNull(10, 0); | |
| leftPad | macro | Pads a string on the left to a specified length | SELECT leftPad('abc', 5, '*'); | |
| lengthUTF8 | macro | Returns the length of a string in UTF-8 characters | SELECT lengthUTF8('Привет'); | |
| match | macro | Performs a regular expression match on a string | SELECT match('abc123', '\d+'); | |
| minus | macro | Performs subtraction of two numbers | SELECT minus(5, 3); | |
| modulo | macro | Calculates the remainder of division (modulus) | SELECT modulo(10, 3); | |
| moduloOrZero | macro | Calculates modulus but returns zero instead of error on division by zero | SELECT moduloOrZero(10, 0); | |
| notEmpty | macro | Check if a string is not empty | SELECT notEmpty('abc'); | |
| numbers | table_macro | Generates a sequence of numbers starting from 0 | Returns a table with a single column (UInt64) | SELECT * FROM numbers(10); |
| parseURL | macro | Extracts parts of a URL | SELECT parseURL('https://clickhouse.com', 'host'); | |
| path | macro | Extracts the path from a URL | SELECT path('https://clickhouse.com/docs'); | |
| plus | macro | Performs addition of two numbers | SELECT plus(5, 3); | |
| protocol | macro | Extracts the protocol from a URL | SELECT protocol('https://clickhouse.com'); | |
| read_parquet_mergetree | function | Merge parquet files using a primary sorting key for fast range queries | experimental | COPY (SELECT * FROM read_parquet_mergetree(['/folder/*.parquet'], 'sortkey') TO 'sorted.parquet'; |
| rightPad | macro | Pads a string on the right to a specified length | SELECT rightPad('abc', 5, '*'); | |
| splitByChar | macro | Splits a string by a given character | SELECT splitByChar(',', 'a,b,c'); | |
| toDayOfMonth | macro | Extracts the day of the month from a date | SELECT toDayOfMonth('2023-09-10'); | |
| toFixedString | macro | Converts a value to a fixed-length string | SELECT toFixedString('abc', 5); | |
| toFloat | macro | Converts a value to a float | SELECT toFloat('123.45'); | |
| toFloatOrNull | macro | Converts a value to float or returns NULL if the conversion fails | SELECT toFloatOrNull('abc'); | |
| toFloatOrZero | macro | Converts a value to float or returns zero if the conversion fails | SELECT toFloatOrZero('abc'); | |
| toHour | macro | Extracts the hour from a DateTime value | SELECT toHour(now()); | |
| toInt128 | macro | Converts a value to a 128-bit integer | SELECT toInt128('123456789012345678901234567890'); | |
| toInt128OrNull | macro | Converts to a 128-bit integer or returns NULL on failure | SELECT toInt128OrNull('abc'); | |
| toInt128OrZero | macro | Converts to a 128-bit integer or returns zero on failure | SELECT toInt128OrZero('abc'); | |
| toInt16 | macro | Converts a value to a 16-bit integer | SELECT toInt16('123'); | |
| toInt16OrNull | macro | Converts to a 16-bit integer or returns NULL on failure | SELECT toInt16OrNull('abc'); | |
| toInt16OrZero | macro | Converts to a 16-bit integer or returns zero on failure | SELECT toInt16OrZero('abc'); | |
| toInt256 | macro | Converts a value to a 256-bit integer | SELECT toInt256('12345678901234567890123456789012345678901234567890123456789012345678901234567890'); | |
| toInt256OrNull | macro | Converts to a 256-bit integer or returns NULL on failure | SELECT toInt256OrNull('abc'); | |
| toInt256OrZero | macro | Converts to a 256-bit integer or returns zero on failure | SELECT toInt256OrZero('abc'); | |
| toInt32 | macro | Converts a value to a 32-bit integer | SELECT toInt32('123'); | |
| toInt32OrNull | macro | Converts to a 32-bit integer or returns NULL on failure | SELECT toInt32OrNull('abc'); | |
| toInt32OrZero | macro | Converts to a 32-bit integer or returns zero on failure | SELECT toInt32OrZero('abc'); | |
| toInt64 | macro | Converts a value to a 64-bit integer | SELECT toInt64('123'); | |
| toInt64OrNull | macro | Converts to a 64-bit integer or returns NULL on failure | SELECT toInt64OrNull('abc'); | |
| toInt64OrZero | macro | Converts to a 64-bit integer or returns zero on failure | SELECT toInt64OrZero('abc'); | |
| toInt8 | macro | Converts a value to an 8-bit integer | SELECT toInt8('123'); | |
| toInt8OrNull | macro | Converts to an 8-bit integer or returns NULL on failure | SELECT toInt8OrNull('abc'); | |
| toInt8OrZero | macro | Converts to an 8-bit integer or returns zero on failure | SELECT toInt8OrZero('abc'); | |
| toMinute | macro | Extracts the minute from a DateTime value | SELECT toMinute(now()); | |
| toMonth | macro | Extracts the month from a Date value | SELECT toMonth('2023-09-10'); | |
| toSecond | macro | Extracts the second from a DateTime value | SELECT toSecond(now()); | |
| toString | macro | Converts a value to a string | SELECT toString(123); | |
| toUInt16 | macro | Converts a value to an unsigned 16-bit integer | SELECT toUInt16('123'); | |
| toUInt16OrNull | macro | Converts to an unsigned 16-bit integer or returns NULL on failure | SELECT toUInt16OrNull('abc'); | |
| toUInt16OrZero | macro | Converts to an unsigned 16-bit integer or returns zero on failure | SELECT toUInt16OrZero('abc'); | |
| toUInt32 | macro | Converts a value to an unsigned 32-bit integer | SELECT toUInt32('123'); | |
| toUInt32OrNull | macro | Converts to an unsigned 32-bit integer or returns NULL on failure | SELECT toUInt32OrNull('abc'); | |
| toUInt32OrZero | macro | Converts to an unsigned 32-bit integer or returns zero on failure | SELECT toUInt32OrZero('abc'); | |
| toUInt64 | macro | Converts a value to an unsigned 64-bit integer | SELECT toUInt64('123'); | |
| toUInt64OrNull | macro | Converts to an unsigned 64-bit integer or returns NULL on failure | SELECT toUInt64OrNull('abc'); | |
| toUInt64OrZero | macro | Converts to an unsigned 64-bit integer or returns zero on failure | SELECT toUInt64OrZero('abc'); | |
| toUInt8 | macro | Converts a value to an unsigned 8-bit integer | SELECT toUInt8('123'); | |
| toUInt8OrNull | macro | Converts to an unsigned 8-bit integer or returns NULL on failure | SELECT toUInt8OrNull('abc'); | |
| toUInt8OrZero | macro | Converts to an unsigned 8-bit integer or returns zero on failure | SELECT toUInt8OrZero('abc'); | |
| toYYYYMM | macro | Formats a Date to 'YYYYMM' string format | SELECT toYYYYMM('2023-09-10'); | |
| toYYYYMMDD | macro | Formats a Date to 'YYYYMMDD' string format | SELECT toYYYYMMDD('2023-09-10'); | |
| toYYYYMMDDhhmmss | macro | Formats a DateTime to 'YYYYMMDDhhmmss' string format | SELECT toYYYYMMDDhhmmss(now()); | |
| toYear | macro | Extracts the year from a Date or DateTime value | SELECT toYear('2023-09-10'); | |
| topLevelDomain | macro | Extracts the top-level domain (TLD) from a URL | SELECT topLevelDomain('https://example.com'); | |
| tupleConcat | macro | Concatenates two tuples into one tuple | SELECT tupleConcat((1, 'a'), (2, 'b')); | |
| tupleDivide | macro | Performs element-wise division between two tuples | SELECT tupleDivide((10, 20), (2, 5)); | |
| tupleDivideByNumber | macro | Divides each element of a tuple by a number | SELECT tupleDivideByNumber((10, 20), 2); | |
| tupleIntDiv | macro | Performs element-wise integer division between two tuples | SELECT tupleIntDiv((10, 20), (3, 4)); | |
| tupleIntDivByNumber | macro | Performs integer division of each element of a tuple by a number | SELECT tupleIntDivByNumber((10, 20), 3); | |
| tupleMinus | macro | Performs element-wise subtraction between two tuples | SELECT tupleMinus((10, 20), (5, 3)); | |
| tupleModulo | macro | Performs element-wise modulus between two tuples | SELECT tupleModulo((10, 20), (3, 6)); | |
| tupleModuloByNumber | macro | Calculates the modulus of each element of a tuple by a number | SELECT tupleModuloByNumber((10, 20), 3); | |
| tupleMultiply | macro | Performs element-wise multiplication between two tuples | SELECT tupleMultiply((10, 20), (2, 5)); | |
| tupleMultiplyByNumber | macro | Multiplies each element of a tuple by a number | SELECT tupleMultiplyByNumber((10, 20), 3); | |
| tuplePlus | macro | Performs element-wise addition between two tuples | SELECT tuplePlus((1, 2), (3, 4)); | |
| url | table_macro | Performs queries against remote URLs using the specified format | Supports JSON, CSV, PARQUET, TEXT, BLOB | SELECT * FROM url('https://urleng.com/test','JSON'); |
| JSONExtract | macro | Extracts JSON data based on key from a JSON object | SELECT JSONExtract(json_column, 'user.name'); | |
| JSONExtractString | macro | Extracts JSON data as a VARCHAR from a JSON object | SELECT JSONExtractString(json_column, 'user.email'); | |
| JSONExtractUInt | macro | Extracts JSON data as an unsigned integer from a JSON object | SELECT JSONExtractUInt(json_column, 'user.age'); | |
| JSONExtractInt | macro | Extracts JSON data as a 32-bit integer from a JSON object | SELECT JSONExtractInt(json_column, 'user.balance'); | |
| JSONExtractFloat | macro | Extracts JSON data as a double from a JSON object | SELECT JSONExtractFloat(json_column, 'user.score'); | |
| JSONExtractRaw | macro | Extracts raw JSON data based on key from a JSON object | SELECT JSONExtractRaw(json_column, 'user.address'); | |
| JSONHas | macro | Checks if a JSON key exists and is not null | SELECT JSONHas(json_column, 'user.active'); | |
| JSONLength | macro | Returns the length of a JSON array | SELECT JSONLength(json_column, 'items'); | |
| JSONType | macro | Determines the type of JSON element at the given path | SELECT JSONType(json_column, 'user.data'); | |
| JSONExtractKeys | macro | Extracts keys from a JSON object | SELECT JSONExtractKeys(json_column); | |
| JSONExtractValues | macro | Extracts all values as text from a JSON object | SELECT JSONExtractValues(json_column); | |
| equals | macro | Checks if two values are equal | SELECT equals(column_a, column_b); | |
| notEquals | macro | Checks if two values are not equal | SELECT notEquals(column_a, column_b); | |
| less | macro | Checks if one value is less than another | SELECT less(column_a, column_b); | |
| greater | macro | Checks if one value is greater than another | SELECT greater(column_a, column_b); | |
| lessOrEquals | macro | Checks if one value is less than or equal to another | SELECT lessOrEquals(column_a, column_b); | |
| greaterOrEquals | macro | Checks if one value is greater than or equal to another | SELECT greaterOrEquals(column_a, column_b); | |
| dictGet | macro | Retrieves an attribute from a VARIABLE string or MAP | SELECT dictGet('dictionary_name', 'attribute'); |
DuckDB ® is a trademark of DuckDB Foundation. ClickHouse® is a trademark of ClickHouse Inc. All trademarks, service marks, and logos mentioned or depicted are the property of their respective owners. The use of any third-party trademarks, brand names, product names, and company names is purely informative or intended as parody and does not imply endorsement, affiliation, or association with the respective owners.