谷歌大查詢中的行之間的差異

Question

我目前正試圖計算谷歌大查詢中的行之間的差異。我實際上有一個工作查詢。

SELECT 
    id, record_time, level, lag, 
    (level - lag) as diff 
FROM (
    SELECT 
     id, record_time, level, 
     LAG(level) OVER (ORDER BY id, record_time) as lag 
    FROM (
     SELECT 
     * 
     FROM 
     TABLE_QUERY(MY_TABLES)) 
    ORDER BY 
     1, 2 ASC 
    ) 
GROUP BY 1, 2, 3, 4 
ORDER BY 1, 2 ASC 

但我使用大數據，有時我有內存限制警告，不讓我執行查詢。所以，我想了解爲什麼我不能做像波紋管這樣的優化查詢。我認爲這將允許在沒有內存限制警告的情況下處理更多記錄。

SELECT 
     id, record_time, level, 
     level - LAG(level, 1) OVER (ORDER BY id, record_time) as diff 
    FROM (
     SELECT 
     * 
     FROM 
     TABLE_QUERY(MY_TABLES)) 
    ORDER BY 
     1, 2 ASC 

這種功能level - LAG(level, 1) OVER (ORDER BY id, record_time) as diff,當執行查詢返回的錯誤

在解析表達式

大上查詢中缺少的功能。

我也試着把()放到這個函數中，但是它不起作用。

感謝您的幫助！

Answer 1

它適合我。也許你忘了enable standard SQL？這裏是一個例子：

WITH Input AS (
    SELECT 1 AS id, TIMESTAMP '2017-10-17 00:00:00' AS record_time, 2 AS level UNION ALL 
    SELECT 2, TIMESTAMP '2017-10-16 00:00:00', 3 UNION ALL 
    SELECT 1, TIMESTAMP '2017-10-16 00:00:00', 4 
) 
SELECT 
id, record_time, level, lag, 
(level - lag) as diff 
FROM (
    SELECT 
    id, record_time, level, 
    LAG(level) OVER (ORDER BY id, record_time) as lag 
    FROM Input 
) 
GROUP BY 1, 2, 3, 4 
ORDER BY 1, 2 ASC;