# Building Expressions

Expressions are JSON like objects which process and return a specific **calculated** output at the runtime. An expressions object looks like -

## Syntax

```json
{
    <operator>: <value>
}
```

### Properties

| Field       | Description                                                                                                                                                                                                      | Required |
| ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- |
| \<operator> | A CQL expression operator which defines what type of computation has to be done in this expression. You can check the list of CQL expression operators [**here**](#list-of-expression-objects-available-in-cql). | true     |
| \<value>    | A list or dict of arguments required for the corresponding CQL operator.                                                                                                                                         | true     |

## Restrictions

You can have **at most 1 CQL operator** per expression object.

## Examples

```json
{
    "$add": [1,2,3]
}
```

The above expression will return **6** when used in any node that supports Expressions.

## List of Expression Operators available in CQL

* [$abs](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdabs)
* [$add](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdadd)
* [$addDate](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdadddate)
* [$arrayElemAt](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdarrayelemat)
* [$avg](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdavg)
* [$buildDateTime](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdbuilddatetime)
* [$ceil](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdceil)
* [$cond](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdcond)
* [$divide](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usddivide)
* [$floor](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdfloor)
* [$ifNull](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdifnull)
* [$max](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdmax)
* [$min](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdmin)
* [$mod](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdmod)
* [$multiply](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdmultiply)
* [$pow](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdpow)
* [$subtract](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdsubtract)
* [$sqrt](https://docs.cosmocloud.io/flow-builder/cql-cosmocloud-query-language/building-expressions/usdsqrt)