選擇與分組

Question

參照這個問題

select all the rows until date diff is 4 from bottom

解決方案中的所有行，直到日期的差異條件匹配的偉大工程，而是如何通過CUSTOMER_ID和第4天差異各CUSTOMER_ID組，第8天和DIFF組

http://sqlfiddle.com/#!2/93d75/3

Answer 1

你只需要跟蹤最新customer_id的和太執行「沒關係」的邏輯：

SELECT amount, customer_id, updated_at, date_diff 
FROM (
    SELECT *, 
      @b:=NOT @c<=>customer_id 
       OR (@b AND DATEDIFF(@t,updated_at)<=date_diff) AS okay, 
      @c:=customer_id, 
      @t:=updated_at 
    FROM  my_table, (SELECT 4 AS date_diff) init 
    ORDER BY customer_id, updated_at DESC 
) t 
WHERE okay 
ORDER BY customer_id, updated_at, id 

請參閱sqlfiddle。