text: -- @author: krakowiakpawel9@gmail.com
  -- @site: e-smartdata.org
  
  -- CAST(expression AS typename)
  SELECT * FROM `bigquery-course-257019.functions.people`;
  
  -- INT64 na FLOAT64
  SELECT *, CAST(age AS FLOAT64) AS age_float FROM `bigquery-course-257019.functions.people`;
  
  -- INT64 na STRING
  SELECT *, CAST(age AS STRING) AS age_string FROM `bigquery-course-257019.functions.people`;
  
  -- CONCAT()
  SELECT *, CONCAT(CAST(age AS STRING), ' years old') AS age_string FROM `bigquery-course-257019.functions.people`;
  
  SELECT
    CAST('001' AS INT64) AS id,
    CAST(2 AS BOOL) AS is_purchased,
    SAFE_CAST('a' AS DATE) AS date_purchased;
  
  