def _get_table_sql_columns(columns=[]):
	"""
	return a string of a list of columns to be inserted into the sql code
	
	Params
	------
	columns=[] (list)

	Return
	------
	sql_columns (str)
	"""

	if len(columns) == 0:
		sql_columns = '*'

	else: 
		sql_columns = ",".join(columns)

	return sql_columns