uniqExact

uniqExact(x[, ...])

CREATE TABLE example_data
(
    id UInt32,
    category String
)
ENGINE = Memory;

INSERT INTO example_data VALUES
(1, 'A'), (2, 'B'), (3, 'A'), (4, 'C'), (5, 'B'), (6, 'A');

SELECT uniqExact(category) as exact_unique_categories
FROM example_data;

┌─exact_unique_categories─┐
│                       3 │
└─────────────────────────┘

SELECT uniqExact(id, category) as exact_unique_combinations
FROM example_data;

┌─exact_unique_combinations─┐
│                         6 │
└───────────────────────────┘