Function julianday 

pub fn julianday<'a, V, E>(
    expr: E,
) -> SQLExpr<'a, V, <V::DialectMarker as DialectTypes>::Double, E::Nullable, E::Aggregate>
where
    V: SQLParam + 'a,
    V::DialectMarker: SQLiteDateTimeSupport,
    E: Expr<'a, V>,
    E::SQLType: Temporal,

JULIANDAY - converts a temporal expression to Julian day number (SQLite).

Returns a dialect-aware double type, preserves nullability.

Example

use drizzle_core::expr::julianday;

// SELECT JULIANDAY(users.created_at)
let julian = julianday(users.created_at);