def _build_col_var_list_str(col_names, var_names):
    """
    Builds the string that contains the list of column to parameterized variable
    assignments for SQL statements.

    Args:
      col_names ([str]): The list of column names.  Order and length MUST match
        that of `var_names`!
      var_names ([str]): The list of var names, likely the keys in the dict
        returned by `_prep_sanitized_vars()`.  Order and length MUST match that
        of `col_names`!

    Returns:
      (str): The single string that contains the list of all <col> = <var>`
        items in comma-separated format, where the vars are parameterized inputs
        (i.e. `%(<>)s`).  An emptry string if no col/var names
    """
    assert len(col_names) == len(var_names), 'Col and vars must be same length!'
    return ', '.join([f'{col_names[i]} = %({var_names[i]})s'
            for i in range(len(col_names))])