presto-parser/src/main/java/io/prestosql/sql/tree/DropColumn.java/DropColumn/DropColumn
class DropColumn:    private DropColumn(Optional<NodeLocation> location, QualifiedName table, Identifier column)
    {
        super(location);
        this.table = requireNonNull(table, "table is null");
        this.column = requireNonNull(column, "column is null");
    }