Trait ExprExt 

pub trait ExprExt {
    // Required methods
    fn with_alias(self, alias: &str) -> Expr;
    fn or_default(self, default: impl Into<Expr>) -> Expr;
    fn json(self, key: &str) -> JsonBuilder;
    fn path(self, dotted_path: &str) -> JsonBuilder;
    fn cast(self, target_type: &str) -> Expr;
    fn upper(self) -> Expr;
    fn lower(self) -> Expr;
    fn trim(self) -> Expr;
    fn length(self) -> Expr;
    fn abs(self) -> Expr;
}

Extension trait to add fluent methods to Expr

Required Methods

fn with_alias(self, alias: &str) -> Expr

Add an alias to this expression.

Example

col("name").with_alias("user_name")

fn or_default(self, default: impl Into<Expr>) -> Expr

COALESCE with a default value.

Example

col("name").or_default("Unknown")  // COALESCE(name, 'Unknown')

fn json(self, key: &str) -> JsonBuilder

JSON text extraction (column->>‘key’).

Example

col("contact_info").json("phone")  // contact_info->>'phone'

fn path(self, dotted_path: &str) -> JsonBuilder

JSON path extraction with dot notation.

Example

col("metadata").path("vessel.0.port")  // metadata->'vessel'->0->>'port'

fn cast(self, target_type: &str) -> Expr

Cast to a type: CAST(expr AS type)

Example

col("value").cast("int")  // CAST(value AS int)

fn upper(self) -> Expr

UPPER(expr)

fn lower(self) -> Expr

LOWER(expr)

fn trim(self) -> Expr

TRIM(expr)

fn length(self) -> Expr

LENGTH(expr)

fn abs(self) -> Expr

ABS(expr)

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl ExprExt for &str

fn with_alias(self, alias: &str) -> Expr

fn or_default(self, default: impl Into<Expr>) -> Expr

fn json(self, key: &str) -> JsonBuilder

fn path(self, dotted_path: &str) -> JsonBuilder

fn cast(self, target_type: &str) -> Expr

fn upper(self) -> Expr

fn lower(self) -> Expr

fn trim(self) -> Expr

fn length(self) -> Expr

fn abs(self) -> Expr

Implementors

impl ExprExt for Expr