Numeric & Utility Functions

DuckDB’s math and trigonometry functions, plus the handful of general-purpose scalars that don’t belong to any other category — conditional null-handling, UUID generation, and runtime utilities. All are free functions in better_duck_diesel::dsl::*.

use diesel::prelude::*;
use better_duck_diesel::dsl::*;

let n: f64 = diesel::select(sqrt(16.0_f64)).get_result(&mut conn)?; // 4.0

Math and trigonometry

Double -> Double unless noted:

Arithmetic & powers

abs<T>(x) (generic, preserves the argument type), sqrt, cbrt, pow(base, exponent), exp, ln, log2, log10, ceil, floor, round, sign.

Trigonometry

sin, cos, tan, asin, acos, atan, atan2(y, x), degrees, radians.

Integer math & bitwise

gcd(a: BigInt, b: BigInt) (→BigInt), lcm(a: BigInt, b: BigInt) (→BigInt), mod_(a, b) (#[sql_name = "mod"], →BigInt), xor(a, b) (→BigInt), bit_count(x: BigInt) (→DuckTinyInt).

Min / max (generic)

greatest<T>(a, b) and least<T>(a, b) — generic over T, returning the same type.

mod_ is spelled with a trailing underscore in Rust and emits mod(...) via #[sql_name = "mod"]. abs, greatest, and least are generic so they preserve the argument’s numeric type rather than forcing Double.

Conditional / null-handling

Generic over T:

Function	Signature	Returns	Meaning
`nullif(a, b)`	`T, T`	`Nullable<T>`	`NULL` when `a = b`, else `a`
`ifnull(a, b)`	`Nullable<T>, T`	`T`	`b` when `a` is `NULL`, else `a`

let safe: f64 = diesel::select(ifnull(products::price.nullable(), 0.0)).first(&mut conn)?;

UUID generation

All return DuckUuid (see Type mapping): gen_random_uuid(), uuidv4(), uuidv7().

use better_duck_diesel::values::Uuid;
let id: Uuid = diesel::select(uuidv7()).get_result(&mut conn)?;

Utility

version() (→Text) returns the DuckDB version string; type_of<T>(x) (#[sql_name = "typeof"], →Text) returns the DuckDB type name of its argument.

let v: String = diesel::select(version()).get_result(&mut conn)?;

String functions

Text transforms, hashing, encoding.

Date & time functions

Temporal extraction and construction.

Aggregates

Statistical and bitwise aggregates.

Type mapping

What Double / BigInt / DuckUuid load as.

Getting Started

CRUD

DuckDB SQL DSL

Types & Pooling

Numeric & Utility Functions

Math and trigonometry

Conditional / null-handling

UUID generation

Utility

See also

String functions

Date & time functions

Aggregates

Type mapping

​Math and trigonometry

​Conditional / null-handling

​UUID generation

​Utility

​See also

String functions

Date & time functions

Aggregates

Type mapping

Math and trigonometry

Conditional / null-handling

UUID generation

Utility

See also