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APPLY modifier

docs/en/sql-reference/statements/select/apply_modifier.md

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APPLY modifier {#apply}

Allows you to invoke some function for each row returned by an outer table expression of a query.

Syntax {#syntax}

sql
SELECT <expr> APPLY( <func> ) FROM [db.]table_name

Example {#example}

sql
CREATE TABLE columns_transformers (i Int64, j Int16, k Int64) ENGINE = MergeTree ORDER by (i);
INSERT INTO columns_transformers VALUES (100, 10, 324), (120, 8, 23);
SELECT * APPLY(sum) FROM columns_transformers;
response
┌─sum(i)─┬─sum(j)─┬─sum(k)─┐
│    220 │     18 │    347 │
└────────┴────────┴────────┘