# sum_if

Calculate revenue only from paid orders. 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:

```sql
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

```sql
SELECT sum_if(amount, status = 'paid') AS paid_result
FROM orders
FORMAT csv;
```

```text
160
```

Selected NULL amounts are skipped. False and NULL conditions do not contribute.

## Empty segments

count_if and sum_if return zero when no qualifying non-NULL value 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](https://coordinatordb.com/docs/reference/functions/aggregate-functions/combinators) for the supported conditional functions and SQL FILTER alternatives.