[BUG] JSQLParser : ClickHouse : COLUMNS APPLY lambda not supported in SELECT

ClickHouse supports the COLUMNS() expression with APPLY, which applies a function or lambda expression to all columns matching a regular expression. JSQLParser fails to parse the lambda expression used by APPLY.

See the ClickHouse docs:

https://clickhouse.com/docs/sql-reference/statements/select

SQL Example

CREATE TABLE metrics
(
    id UInt32,
    metric_cpu Float64,
    metric_memory Float64,
    metric_disk Float64,
    hostname String
)
ENGINE = MergeTree
ORDER BY id;

INSERT INTO metrics
    (id, metric_cpu, metric_memory, metric_disk, hostname)
VALUES
    (1, 12.34567, 78.90123, 45.67891, 'server-1'),
    (2, 98.76543, 23.45678, 67.89012, 'server-2'),
    (3, 55.55555, 44.44444, 88.88888, 'server-3');

SELECT
    COLUMNS('^metric_')
    APPLY(x -> round(x, 2))
FROM metrics;

The query executes successfully in ClickHouse and returns the matching metric_* columns with round(x, 2) applied to each column.

Parsing error

ParseException: Encountered: "->" / "->", at line 3, column 13, in lexical state DEFAULT.
Was expecting one of these terminals within expansion starting at 6349:13:
<K_COMMA> (inside 6348:17) ...
<CLOSING_BRACKET> (inside 6349:13) ...

The failure appears to be caused by JSQLParser not accepting the ClickHouse lambda expression syntax:

x -> round(x, 2)

inside COLUMNS(...) APPLY(...).

Tested with ClickHouse 26.8.

Please call me when SQL has gotten turned into a turing complete, self-aware, eval() like code modification engine.

Deal : leave the number with me. I'll watch the grammar and call you when it starts parsing itself.

... and call you when it starts parsing itself.

To kill it before it grows into something too dangerous :-D
Forgive me my sarcasm, I am perhaps just too old for all of this.

Next episode: the self-replicating SQL rootkit inside the UEFI firmware -- when assembler became too inefficient. You have been warned!

feat: support ClickHouse COLUMNS(...) APPLY/EXCEPT/REPLACE transforme…

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[BUG] JSQLParser : ClickHouse : COLUMNS APPLY lambda not supported in SELECT #2631

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[BUG] JSQLParser : ClickHouse : COLUMNS APPLY lambda not supported in SELECT #2631

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SQL Example

Parsing error

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manticore-projects commented on Sep 13, 2026

fudianchn commented on Sep 13, 2026

manticore-projects commented on Sep 13, 2026

manticore-projects commented on Sep 13, 2026

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