---
title: Boolean and numeric literals in query strings
sidebar_label: Boolean & numeric
---

A literal value is one that is explicitly defined in code rather than computed or derived from other values. In the query language, literals are commonly used to define constant values in expressions. This guide covers boolean and numeric literals in query strings. Since query strings use Java syntax for literals, they follow Java conventions, which differ from Python syntax.

## Boolean literals

In the Deephaven Query Language (DQL), there are only two boolean literal values: `true` and `false` (lowercase). In Python, the boolean literals are `True` and `False` (uppercase). This difference is important—if you use Python-style literals in a query string, the query engine will look for variables or columns named `True` or `False`, which may not exist.

The following code uses both boolean literals:

```python order=source,source_meta
from deephaven import empty_table

source = empty_table(1).update(["TrueLiteral = true", "FalseLiteral = false"])
source_meta = source.meta_table
```

## Numeric literals

Numeric literals in the query language can be integers or floating-point numbers. By default, an integer literal is treated as a 32-bit signed integer (Java primitive `int`), and a floating-point literal is treated as a 64-bit floating-point number (Java primitive `double`). You can specify the type of a numeric literal by appending a suffix to the number:

- `L` or `l` for a 64-bit signed integer (Java primitive `long`).
- `f` for a 32-bit floating-point number (Java primitive `float`).

The following example constructs four columns, each with a numeric literal. The table metadata is also shown:

```python order=source,source_meta
from deephaven import empty_table

source = empty_table(1).update(
    [
        "IntLiteral = 5",
        "IntOctalLiteral = 0123",
        "IntHexadecimalLiteral = 0xABCD",
        "IntBinaryLiteral = 0b1010",
        "LongLiteral = 123456789L",
        "FloatLiteral = 3.14f",
        "DoubleLiteral = 3.14",
        "FloatScientificLiteral = 1.23e3f",
        "DoubleScientificLiteral = 1.23e3",
        "FloatHexadecimalLiteral = 0x1.23p3f",
        "DoubleHexadecimalLiteral = 0x1.23p3",
        "IntUnderscoreLiteral = 1_000_000",
        "LongUnderscoreLiteral = 500_000_000L",
        "FloatUnderscoreLiteral = 9_876.543_210f",
        "DoubleUnderscoreLiteral = 1_232.815_679",
    ]
)
source_meta = source.meta_table
```

## Related documentation

- [String and char literals](./string-char-literals.md)
- [Date-time literals](./date-time-literals.md)
- [`empty_table`](../reference/table-operations/create/emptyTable.md)
- [`meta_table`](../reference/table-operations/metadata/meta_table.md)