Bool | ClickHouse Docs

Type bool is internally stored as UInt8. Possible values are true (1), false (0).

SELECT true AS col, toTypeName(col);
┌

CREATE TABLE test_bool
(
    `A` Int64,
    `B` Bool
)
ENGINE = Memory;

INSERT INTO test_bool VALUES (1, true),(2,0);

SELECT * FROM test_bool;
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