Function convert_projection

nodedb-sql/src/planner/select/helpers.rs:15–58

Convert SELECT projection items.

(items: &[ast::SelectItem])

/// Convert SELECT projection items.
pub fn convert_projection(items: &[ast::SelectItem]) -> Result<Vec<Projection>> {
    let mut result = Vec::new();
    for item in items {
        match item {
            ast::SelectItem::UnnamedExpr(expr) => {
                let sql_expr = convert_expr(expr)?;
                match &sql_expr {
                    SqlExpr::Column { table, name } => {
                        result.push(Projection::Column(qualified_name(table.as_deref(), name)));
                    }
                    SqlExpr::Wildcard => {
                        result.push(Projection::Star);
                    }
                    _ => {
                        result.push(Projection::Computed {
                            expr: sql_expr,
                            alias: format!("{expr}").to_lowercase(),
                        });
                    }
                }
            }
            ast::SelectItem::ExprWithAlias { expr, alias } => {
                let sql_expr = convert_expr(expr)?;
                result.push(Projection::Computed {
                    expr: sql_expr,
                    alias: normalize_ident(alias),
                });
            }
            ast::SelectItem::Wildcard(_) => {
                result.push(Projection::Star);
            }
            ast::SelectItem::QualifiedWildcard(kind, _) => {
                let table_name = match kind {
                    ast::SelectItemQualifiedWildcardKind::ObjectName(name) => {
                        crate::parser::normalize::normalize_object_name_checked(name)?
                    }
                    _ => String::new(),
                };
                result.push(Projection::QualifiedStar(table_name));
            }
        }
    }
    Ok(result)
}

/// Build a qualified column reference (`table.name` or just `name`).
pub fn qualified_name(table: Option<&str>, name: &str) -> String {