ScanSource.project
ScanSource project(scope string[] columns) @safeA source reading only columns (a proper subset of the schema's names); the error policy is the source's own (the approved rule: only error-free column reads may be skipped).
ScanSource project(scope string[] columns) @safeA source reading only columns (a proper subset of the schema's names); the error policy is the source's own (the approved rule: only error-free column reads may be skipped).