# avg

Calculates the arithmetic mean of numeric values. `NULL` values are skipped.

**Syntax**

```text
avg(x)
```

**Arguments**

* `x` — A numeric column or expression. Integers, floating-point numbers, and
  decimals are supported. Legacy text and blob inputs use SQL numeric conversion.
  Convert native dates, times, intervals, and other nonnumeric values explicitly
  before averaging them.

**Returned value**

Returns a `REAL` mean for ordinary numeric inputs, or an exact decimal mean for
native decimal inputs. Empty or all-`NULL` input returns `NULL`.

Do not mix native decimals with approximate inputs without an explicit cast.
Exact overflow raises `NUMERIC_OVERFLOW`.

**Examples**

**Basic usage**

```sql
CREATE TABLE measurements (x Int8);
INSERT INTO measurements VALUES (0), (1), (2), (3), (4), (5);
```

```sql
SELECT avg(x) FROM measurements FORMAT csv;
```

```text
2.5
```

**Empty table returns NULL**

```sql
CREATE TABLE test (t UInt8);
```

```sql
SELECT avg(t) FROM test FORMAT csv;
```

```text
\N
```

**Average request duration**

Use a numeric duration in a known unit:

```sql
CREATE TABLE requests (req_id Int64, duration_ms UInt32);
INSERT INTO requests VALUES (1, 100), (2, 200), (3, 300);
```

```sql
SELECT avg(duration_ms) AS avg_duration_ms FROM requests FORMAT csv;
```

```text
200.0
```