DSL Coverage

DSL Functionality overview

Version

Scala DSL v0.8.0

Clickhouse v18.12.17

Intro

Below is a list of categories of functionalities offered by the ClickHouse SQL language.

For each category a link to a detail page is provided, as well as an indication of the coverage of the DSL for this functionality.

Queries

Functionality	DSL Doc	Clickhouse Doc	Supported	Comments
SELECT		Doc	Yes
- DISTINCT			Yes
- FROM			Yes
- FINAL			Yes
- ARRAY JOIN			No	Supported as a column operator [link]
- JOIN			Yes	With the exception of GLOBAL JOIN
- PREWHERE			No	Low hanging fruit
- WHERE			Yes
- GROUP BY			Yes
- HAVING			Yes
- ORDER BY			Yes
- LIMIT			Yes
- LIMIT n BY			No
- UNION ALL			Yes
- INTO OUTFILE			No
- FORMAT			Yes
- SELECT … IN …			Yes
INSERT			See comments	Experimental, with a hardwired dependency on Spray JSON
CREATE DATABASE			Yes
CREATE TABLE	Doc		Yes	Currently doesnt use the DSL tokenizer, but depends on .toString(), will be changed in the future
CREATE VIEW			No
ATTACH			No
DROP			No
DETACH			No
RENAME			No
ALTER			Yes
SHOW DATABASES/TABLES etc.			No
DESCRIBE TABLE			No
EXISTS			No
USE			See comments	Not needed. We choose to define the database trough an implicit val` in the clickhouse client
SET			No
OPTIMIZE			No
KILL QUERY			No

Operators

Functionality	DSL Doc	Clickhouse Doc	Supported	Comments
Access operators		Doc	Partly	Used in some array functions as part of their API, you can use the "command style" alternative in the DSL
Numeric negation operator			Yes
Multiplication and division operators			Yes
Addition and subtraction operators			Yes
Comparison operators			Yes
Operators for working with data sets			Yes
Logical negation operator			Yes
Logical AND operator			Yes
Logical OR operator			Yes
Conditional operator			Yes
Conditional expression			Yes
Concatenation operator			Yes
Lambda creation operator			Yes	Used in partial functions as part of their API
Array creation operator			Yes	Used in functions accepting collections as part of their API, you can use the command style alternative in the DSL
Tuple creation operator			Yes	Used in IN functions as part of their API

Column functions

Functionality	DSL Doc	Clickhouse Doc	Supported	Comments
Arithmetic functions		Doc	Yes
Comparison functions			Yes
Logical functions			Yes
Type conversion functions			Yes
Functions for working with dates and times			Yes	The DSL offers a timeseries function to group results by a custom interval [link]
Functions for working with strings			Yes
Functions for searching strings			Yes
Functions for searching and replacing in strings			Yes
Conditional functions			Yes
Mathematical functions			Yes
Rounding functions			Yes
Functions for working with arrays			Yes
Functions for splitting and merging strings and arrays			Yes
Bit functions			Yes
Hash functions			Yes
Functions for generating pseudo-random numbers			Yes
Encoding functions			Yes
Functions for working with URLs			Yes
Functions for working with IP addresses			Yes
Functions for working with JSON.			Yes
Higher-order functions			Yes
Other functions			Yes
Functions for working with external dictionaries			Yes
Functions for working with Yandex.Metrica dictionaries			Yes
Functions for implementing the IN operator			Yes
arrayJoin function			Yes

Aggregation Functions

Functionality	DSL Doc	Clickhouse Doc	Supported	Comments
Aggregate functions		Doc	Yes
Aggregate function combinators			Yes
Parametric aggregate functions			No