Function datafusion_expr::expr_fn::col

pub fn col(ident: impl Into<Column>) -> Expr

Create a column expression based on a qualified or unqualified column name. Will normalize unquoted identifiers according to SQL rules (identifiers will become lowercase).

For example:

let c1 = col("a");
let c2 = col("A");
assert_eq!(c1, c2);

// note how quoting with double quotes preserves the case
let c3 = col(r#""A""#);
assert_ne!(c1, c3);