---
last_updated: "2026-09-22T10:48:47.000Z"
title: Bool data type
meta:
    description: Documentation for the Bool data type.
headingMaxLevels: 2
---

# Bool data type {% id="bool" %}

The `Bool` data type represents a truth value, storing either `true` or `false`. Internally, it is stored as an 8-bit unsigned integer (`UInt8`), where `true` corresponds to `1` and `false` to `0`.

```sql
SELECT true AS col, toTypeName(col)
```

Result:

```text
┌─col──┬─toTypeName(true)─┐
│ true │ Bool             │
└──────┴──────────────────┘
```

```sql
SELECT true == 1 AS col, toTypeName(col)
```

Result:

```text
┌─col─┬─toTypeName(equals(true, 1))─┐
│   1 │ UInt8                       │
└─────┴─────────────────────────────┘
```