presto-parser/src/main/java/io/prestosql/sql/SqlFormatter.java/SqlFormatter/visitDropColumn
class SqlFormatter:        @Override
        protected Void visitDropColumn(DropColumn node, Integer context)
        {
            builder.append("ALTER TABLE ")
                    .append(formatName(node.getTable()))
                    .append(" DROP COLUMN ")
                    .append(formatExpression(node.getColumn()));

            return null;
        }