# Azure Digital Twins query language reference: Operators

This document contains reference information on *operators* for the Azure Digital Twins query language.

## Comparison operators

The following operators from the comparison family are supported.

`=`

,`!=`

: Used to compare equality of expressions.`<`

,`>`

: Used for ordered comparison of expressions.`<=`

,`>=`

: Used for ordered comparison of expressions, including equality.

### Example

Here's an example using `=`

. The following query returns twins whose Temperature value is equal to 80.

```
SELECT *
FROM DIGITALTWINS DT
WHERE DT.Temperature = 80
```

Here's an example using `<`

. The following query returns twins whose Temperature value is less than 80.

```
SELECT *
FROM DIGITALTWINS DT
WHERE DT.Temperature < 80
```

Here's an example using `<=`

. The following query returns twins whose Temperature value is less than or equal to 80.

```
SELECT *
FROM DIGITALTWINS DT
WHERE NOT DT.Temperature <= 80
```

## Contains operators

The following operators from the contains family are supported.

`IN`

: Evaluates to true if a given value is in a set of values.`NIN`

: Evaluates to true if a given value isn't in a set of values.

### Example

Here's an example using `IN`

. The following query returns twins whose `owner`

property is one of several options from a list.

```
SELECT *
FROM DIGITALTWINS DT
WHERE DT.owner IN ['John', 'Anil', 'Bailey', 'Alex']
```

## Logical operators

The following operators from the logical family are supported:

`AND`

: Used to connect two expressions, evaluates to true if they're both true.`OR`

: Used to connect two expressions, evaluates to true if at least one of them is true.`NOT`

: Used to negate an expression, evaluates to true if the expression condition isn't met.

### Example

Here's an example using `AND`

. The following query returns twins who meet both conditions of Temperature less than 80 and Humidity less than 50.

```
SELECT *
FROM DIGITALTWINS DT
WHERE DT.Temperature < 80 AND DT.Humidity < 50
```

Here's an example using `OR`

. The following query returns twins who meet at least one of the conditions of Temperature less than 80 and Humidity less than 50.

```
SELECT *
FROM DIGITALTWINS DT
WHERE DT.Temperature < 80 OR DT.Humidity < 50
```

Here's an example using `NOT`

. The following query returns twins who don't meet the conditions of Temperature less than 80.

```
SELECT *
FROM DIGITALTWINS DT
WHERE NOT DT.Temperature < 80
```

## Limitations

The following limits apply to queries using operators.

See the section below for more details.

### Limit for IN/NIN

The limit for the number of values that can be included in an `IN`

or `NIN`

set is 100 values.

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