InfluxDB uses an InfluxQL-like predicate syntax to determine what data
[points](/influxdb/version/reference/glossary/#point) to delete.
InfluxDB uses the delete predicate to evaluate the [series keys](/influxdb/version/reference/glossary/#series-key)
of points in the time range specified in the delete request.
Points with series keys that evaluate to `true` for the given predicate are deleted.
Points with series keys that evaluate to `false` are preserved.

A delete predicate is comprised of one or more [predicate expressions](/influxdb/version/reference/glossary/#predicate-expression).
The left operand of the predicate expression is the column name.
The right operand is the column value.
Operands are compared using [comparison operators](#comparison-operators).
Use [logical operators](#logical-operators) to combine two or more predicate expressions.

##### Example delete predicate
```sql
key1="value1" AND key2="value"
```

{{% note %}}
#### Predicates with special characters or keywords
If your predicate contains keywords or strings with special characters, wrap each in escaped
quotes to ensure the predicate string is parsed correctly.

Because delete predicates follow [InfluxQL](/influxdb/version/reference/syntax/influxql) syntax, [any InfluxQL keyword](/influxdb/version/reference/syntax/influxql/spec/#keywords)
that matches your tag name needs to be escaped. Keywords are case-insensitive.

```js
// Escaped due to the "-"
"_measurement=\"example-dash\""

// Escaped because "Name" is a keyword
"_measurement=example and \"Name\"=predicate"
```
{{% /note %}}

{{% warn %}}
#### Column limitations when deleting data
**InfluxDB {{< current-version >}}** supports deleting data by any column or tag
_**except**_ the following:

- `_time`
{{% show-in "v2" %}}- `_field`{{% /show-in %}}
- `_value`

{{% show-in "v2" %}}

_InfluxDB {{< current-version >}} does not support deleting data **by field**._

{{% /show-in %}}

{{% /warn %}}

## Logical operators
Logical operators join two or more predicate expressions.

| Operator | Description                                                                  |
|:-------- |:-----------                                                                  |
| `AND`    | Both left and right operands must be `true` for the expression to be `true`. |

## Comparison operators
Comparison operators compare left and right operands and return `true` or `false`.

| Operator | Description  | Example        | Result |
|:-------- |:-----------  |:-------:       |:------:|
| `=`      | Equal to     | `"abc"="abc"`  | `true` |

## Delete predicate examples

- [Delete points by measurement](#delete-points-by-measurement)
{{% show-in "cloud,cloud-serverless" %}}- [Delete points by field](#delete-points-by-field){{% /show-in %}}
- [Delete points by tag set](#delete-points-by-tag-set)

### Delete points by measurement
The following will delete points in the `sensorData` measurement:

```sql
_measurement="sensorData"
```

{{% show-in "cloud,cloud-serverless" %}}

### Delete points by field
The following will delete points with the `temperature` field:

```sql
_field="temperature"
```

{{% /show-in %}}

### Delete points by tag set
The following will delete points from the `prod-1.4` host in the `us-west` region:

```sql
host="prod-1.4" AND region="us-west"
```

## Limitations
The delete predicate syntax has the following limitations.

- Delete predicates do not support regular expressions.
- Delete predicates do not support the `OR` logical operator.
- Delete predicates only support equality (`=`), not inequality (`!=`).
- Delete predicates can use any column or tag **except** `_time`
  {{% show-in "v2" %}}, `_field`, {{% /show-in %}}or `_value`.