> ## Documentation Index
> Fetch the complete documentation index at: https://arize-ax.mintlify.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Conditionals and Filters

> Additional flexibility when composing a query

## Conditionals and Filters Overview

**Conditions** are used to define what logic is to be executed based on the status of some condition being satisfied. **Filters** are expressions used to specify a subset of the data items.

### CASE

Case statement. Expressions are evaluated in order, and the first to evaluate to true is returned.

ELSE returns a default value if no statement evaluates to true. If there is no ELSE condition and no case evaluates to true, then NULL is returned.

**Operator**

```swift theme={null}
CASE
WHEN exprs THEN result1
[ WHEN exprs THEN result2 ]
…
[ ELSE default ]
END
```

**Example**

```powershell theme={null}
CASE
WHEN state = 'CA' THEN 1
WHEN score > 500 THEN 1
ELSE 0
END
```

### CASE **expression**

“Simple” case statement. This is similar to the above, except on checks equality between a common expression and values\*\*.\*\*

**Operator**

```csharp theme={null}
CASE expression
WHEN value THEN result
[WHEN ...]
[ELSE result]
END
```

**Example**

```powershell theme={null}
CASE state
WHEN 'CA' THEN 1
WHEN 'TX' THEN 1
ELSE 0
END
```

### **WHERE clause**

Where clause. Takes a list of filter expressions.

NOTE: we do not currently support subqueries in WHERE clauses\*\*.\*\*

**Operator**

```powershell theme={null}
WHERE filter_exprs [ AND | OR filter_exprs ]
```

**Example**

```java theme={null}
WHERE 
state = 'CA'
```

### FILTER

Filter with a where clause. The where clause only applies to the aggregation preceding the FILTER keyword. Otherwise, the WHERE clause is identical to any other WHERE clause.

**Operator**

```
aggregate_function( * ) [ FILTER ( WHERE filter_exprs ) ]
```

**Example**

```java theme={null}
COUNT(*) 
FILTER (
  WHERE 
  state = 'CA' OR state = 'TX'
)
```