count_if ​

Count orders whose status is paid. A conditional aggregate admits rows whose condition is SQL true, so one query can calculate a segment without filtering every other aggregate to that same segment.

Prepare the input ​

The sample includes two paid orders and one pending order:

CREATE TABLE orders(id UInt32, status String, amount Int64);
INSERT INTO orders VALUES (1, 'paid', 100), (2, 'paid', 60), (3, 'pending', 40);

Calculate the segment ​

SELECT count_if(status = 'paid') AS paid_result
FROM orders
FORMAT csv;

2

The function counts matching rows even when another field is NULL.

Empty segments ​

count_if and sum_if return zero when no qualifying row contributes. Arguments are evaluated before the condition is tested; an excluded row does not protect an argument expression from an evaluation error.

See aggregate combinators for the supported conditional functions and SQL FILTER alternatives.