# Aggregate Operators

Available in Seq SQL queries

The following operators can be used in aggregate SQL Queries.

## Any/All

Given an expression, return `true`

if the expression is `true`

for `any`

or `all`

events in the stream.

```
select any(@Level = 'Error') from stream
```

## Count

Given a property name, computes the number of events that have a non-`null`

value for that property.

The special property name `*`

can be used to count all events.

```
select count(*) from stream where has(@Exception)
```

## Distinct

Given a property name or expression, computes the set of distinct values for that expression.

```
select distinct(ExceptionType) from stream where Application like 'Admissions%'
```

`distinct()`

and `count()`

can be combined to count distinct values without returning them all.

```
select count(distinct(ExceptionType)) from stream
```

## First/Last

Given an expression, returns the value of that expression applied to the first or last events in the target range.

```
select first(Elapsed), last(Elapsed) from stream group by time(5m)
```

## Min/Max

Given a numeric expression or property name, computes the smallest or largest value for that expression.

```
select min(Elapsed / 1000) as ElapsedSeconds from stream group by time(1h)
```

## Mean

Computes the arithmetic mean (average) of a numeric expression or property, i.e. `sum(expr) / count(expr)`

.

```
select mean(ItemCount) from stream group by ItemId
```

Events where the expression is null or not numeric are ignored and do not contribute to the final result.

## Names

Returns one row for each property name encountered on matched events. *Added in Seq 3.1.*

```
select names() from stream
```

## Percentile

Given an expression and a percentage `p`

, calculates the value of the expression at or below which `p`

percent of the results fall.

```
select percentile(ResponseTime, 95) from stream group by time(1h), MachineName
```

This is the nearest rank percentile.

## Sum

Given an expression or property name, calculates the sum of that value.

```
select sum(ItemsOrdered) from stream group by ItemId
```

Non-numeric results are ignored.

## Top/Bottom

Selects the first or last `n`

values of an expression.

```
select top(ExceptionType, 10) from stream where Application <> 'Admissions'
```

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