projections.md

Projection builders (Reference)

Projection builders are the current semantic target for scalar expressions in computed columns and other row-level positions.

Functions

Builder	Signature	Meaning
col	def col(name: str) -> ColumnExpr	Named column reference.
lit	def lit(value: int | float | str | bool) -> ColumnExpr	Canonical scalar literal.
int_expr	def int_expr(value: int) -> ColumnExpr	Integer literal expression.
float_expr	def float_expr(value: float) -> ColumnExpr	Float literal expression.
str_expr	def str_expr(value: str) -> ColumnExpr	String literal expression.
bool_expr	def bool_expr(value: bool) -> ColumnExpr	Boolean literal expression.
add	def add(left: ColumnExpr, right: ColumnExpr) -> ColumnExpr	Binary addition.
mul	def mul(left: ColumnExpr, right: ColumnExpr) -> ColumnExpr	Binary multiplication.
eq	def eq(left: ColumnExpr, right: ColumnExpr) -> ColumnExpr	Equality predicate.
gt	def gt(left: ColumnExpr, right: ColumnExpr) -> ColumnExpr	Greater-than predicate.

Dataset entrypoint

def with_column(self, name: str, expr: ColumnExpr) -> Self

• missing name: append at end
• existing name: replace in place

Example

from pub::inql.functions import add, col, lit, mul

projected = (
    orders
        .with_column("amount_x2", mul(col("amount"), lit(2)))
        .with_column("amount_plus_one", add(col("amount"), lit(1)))
)

Capability notes

• with_column(...) is the explicit computed-column entrypoint.
• Projection-list selection, query-block projection sugar, and alias-free symbolic surfaces lower to this scalar-expression model when exposed.
• The typed literal helpers construct the same scalar-literal representation as lit(...).