code: def col(name: str) -> Expression:
      """
      Creates an expression which refers to a table's column.
  
      Example:
      ::
  
          >>> tab.select(col("key"), col("value"))
  
      :param name: the field name to refer to
  
      .. seealso:: :func:`~pyflink.table.expressions.with_all_columns`
      """
      return _unary_op("col", name)
  
imports: from typing import Union
  from pyflink import add_version_doc
  from pyflink.java_gateway import get_gateway
  from pyflink.table.expression import Expression, _get_java_expression, TimePointUnit, JsonOnNull
  from pyflink.table.types import _to_java_data_type, DataType
  from pyflink.table.udf import UserDefinedFunctionWrapper
  from pyflink.util.java_utils import to_jarray, load_java_class
label_desc: Use image node_id 8 for calling a global function with example usage: col(name) and returns: _unary_op