find_cyber_week - BigQuery

SELECT `justfunctions.eu.find_cyber_week`("2023-11-24")
                                            
/*--Output--
1 | Black Friday
*/

CREATE OR REPLACE FUNCTION `your_project_id.your_dataset_id.find_cyber_week`(`date` DATE) 
  RETURNS STRUCT<is_cyber_week INT64, day_name STRING> AS ((
  WITH calculated_dates AS (
    SELECT 
      DATE_ADD(DATE_TRUNC(DATE(EXTRACT(YEAR FROM date), 11, 1), MONTH), 
        INTERVAL (26 - EXTRACT(DAYOFWEEK FROM DATE(EXTRACT(YEAR FROM date), 11, 1))) DAY) AS thanksgiving
  )
  SELECT 
    STRUCT(
    IF(date BETWEEN thanksgiving AND DATE_ADD(thanksgiving, INTERVAL 4 DAY), 1, 0),
    CASE 
      WHEN date = thanksgiving THEN 'Thanksgiving'
      WHEN date = DATE_ADD(thanksgiving, INTERVAL 1 DAY) THEN 'Black Friday'
      WHEN date = DATE_ADD(thanksgiving, INTERVAL 2 DAY) OR date = DATE_ADD(thanksgiving, INTERVAL 3 DAY) THEN 'Thanksgiving Weekend'
      WHEN date = DATE_ADD(thanksgiving, INTERVAL 4 DAY) THEN 'Cyber Monday'
      ELSE NULL
    END)
  FROM calculated_dates
))
  OPTIONS ( description = '''Determines if a <date> falls within Cyber Week and identifies the specific day (e.g., Thanksgiving, Black Friday).''')

SQL User Defined Function (SQL UDF)