text: SELECT EXTRACT (YEAR FROM fecha_incorporacion) AS anio_incorporacion
  FROM platzi.alumnos;
  
  SELECT DATE_PART('YEAR', fecha_incorporacion) AS anio_incorporacion
  FROM platzi.alumnos;
  
  SELECT DATE_PART('YEAR', fecha_incorporacion) AS anio_incorporacion,
  	DATE_PART('MONTH', fecha_incorporacion) AS mes_incorporacion,
  	DATE_PART('DAY', fecha_incorporacion) AS dia_incorporacion
  FROM platzi.alumnos;
  
  SELECT DATE_PART('HOUR', fecha_incorporacion) AS hora_incorporacion,
  	DATE_PART('MINUTE', fecha_incorporacion) AS minuto_incorporacion,
  	DATE_PART('SECOND', fecha_incorporacion) AS segundo_incorporacion
  FROM platzi.alumnos;
  
  SELECT *
  FROM platzi.alumnos
  WHERE(EXTRACT(YEAR FROM fecha_incorporacion)) = 2019;
  
  SELECT *
  FROM platzi.alumnos
  WHERE(DATE_PART('YEAR', fecha_incorporacion)) = 2019;
  
  SELECT *
  FROM (
  	SELECT *,
  		DATE_PART('YEAR', fecha_incorporacion) AS anio_incorporacion
  	FROM platzi.alumnos
  ) AS alumnos_con_anio
  WHERE anio_incorporacion = 2020;
  
  SELECT *
  FROM (
  	SELECT *,
  		DATE_PART('YEAR', fecha_incorporacion) AS anio_incorporacion,
  		DATE_PART('MONTH', fecha_incorporacion) AS mes_incorporacion
  	FROM platzi.alumnos
  ) AS alumnos_con_anio
  WHERE anio_incorporacion = 2020 AND mes_incorporacion = 05;