---
title: Logical Functions reference
meta:
    description: Functions for performing logical operations on values.
headingMaxLevels: 2
---

# Logical functions

The following functions perform logical operations on arguments, treating `0` as `false` and any non-zero value as `true`. They return `0` (false) or `1` (true) as a `UInt8`, or `NULL` in certain cases.

## and

Calculates the logical conjunction (AND) of multiple input values. It returns `true` if all values are `true`, otherwise `false` or `NULL`.

The behavior of `and` can be affected by the `short_circuit_function_evaluation` setting. When enabled, subsequent arguments are only evaluated if necessary to determine the final result, potentially preventing errors from expressions that would otherwise fail.

### Syntax

```sql
and(val1, val2...)
```

Alias: The AND operator.

### Arguments

- `val1, val2, ...`: Numeric values (Int, UInt, Float) or Nullable. At least two values are required.

### Returns

- `0` (false) if any argument evaluates to `false`.
- `NULL` if no argument is `false` but at least one argument is `NULL`.
- `1` (true) otherwise (all arguments are `true`).

Type: `UInt8` or `Nullable(UInt8)`.

### Example

```sql
SELECT and(0, 1, -2)
```

Result:

```result
┌─and(0, 1, -2)─┐
│             0 │
└───────────────┘
```

With `NULL`:

```sql
SELECT and(NULL, 1, 10, -2)
```

Result:

```result
┌─and(NULL, 1, 10, -2)─┐
│                 ᴺᵁᴸᴸ │
└──────────────────────┘
```

## or

Computes the logical disjunction (OR) of multiple input values. It returns `true` if at least one value is `true`, otherwise `false` or `NULL`.

The `short_circuit_function_evaluation` setting can influence how `or` evaluates its arguments. If enabled, arguments are processed only until a `true` value is found, which can optimize performance or prevent errors from unneeded evaluations.

### Syntax

```sql
or(val1, val2...)
```

Alias: The OR operator.

### Arguments

- `val1, val2, ...`: Numeric values (Int, UInt, Float) or Nullable. At least two values are required.

### Returns

- `1` (true) if any argument evaluates to `true`.
- `0` (false) if all arguments evaluate to `false`.
- `NULL` if all arguments are `false` and at least one argument is `NULL`.

Type: `UInt8` or `Nullable(UInt8)`.

### Example

```sql
SELECT or(1, 0, 0, 2, NULL)
```

Result:

```result
┌─or(1, 0, 0, 2, NULL)─┐
│                    1 │
└──────────────────────┘
```

With `NULL`:

```sql
SELECT or(0, NULL)
```

Result:

```result
┌─or(0, NULL)─┐
│        ᴺᵁᴸᴸ │
└─────────────┘
```

## not

Inverts the logical state of a single input value. It returns `true` if the input is `false`, and `false` if the input is `true`.

### Syntax

```sql
not(val)
```

Alias: The Negation operator.

### Arguments

- `val`: A numeric value (Int, UInt, Float) or Nullable.

### Returns

- `1` (true) if `val` evaluates to `false`.
- `0` (false) if `val` evaluates to `true`.
- `NULL` if `val` is `NULL`.

Type: `UInt8` or `Nullable(UInt8)`.

### Example

```sql
SELECT NOT(1)
```

Result:

```result
┌─not(1)─┐
│      0 │
└────────┘
```

## xor

Computes the logical exclusive disjunction (XOR) of two or more values. For multiple inputs, it applies XOR sequentially.

### Syntax

```sql
xor(val1, val2...)
```

### Arguments

- `val1, val2, ...`: Numeric values (Int, UInt, Float) or Nullable. At least two values are required.

### Returns

- For two values: `1` (true) if exactly one value is `true`.
- For two values: `0` (false) if both values are `true` or both are `false`.
- `NULL` if any input is `NULL`.

Type: `UInt8` or `Nullable(UInt8)`.

### Example

```sql
SELECT xor(0, 1, 1)
```

Result:

```result
┌─xor(0, 1, 1)─┐
│            0 │
└──────────────┘
```