DATE_DIFF

1
SELECT
2
  name,
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  birth_date,
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  DATE_DIFF(CURRENT_DATE(), birth_date, YEAR) as age_years,
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  DATE_DIFF(CURRENT_DATE(), birth_date, DAY) as age_days
6
FROM `project.dataset.users`;

1
SELECT
2
  order_id,
3
  order_date,
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  LAG(order_date) OVER (PARTITION BY customer_id ORDER BY order_date) as prev_order,
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  DATE_DIFF(order_date, LAG(order_date) OVER (PARTITION BY customer_id ORDER BY order_date), DAY) as days_since_last
6
FROM `project.dataset.orders`;

1
SELECT
2
  employee_id,
3
  hire_date,
4
  DATE_DIFF(CURRENT_DATE(), hire_date, MONTH) as months_employed
5
FROM `project.dataset.employees`
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WHERE status = 'active';