Redshift - 除以零誤差

Question

我遇到以下問題，不斷拋出“除以零”錯誤

下面給出的是我正在使用的查詢：

select cust_name,
sum(case WHEN sale_date > CURRENT_TIMESTAMP-14 AND sale_date < CURRENT_TIMESTAMP then 1 else 0  END) AS "0_2_sales_count",
sum(case WHEN sale_date > CURRENT_TIMESTAMP-28 AND sale_date < CURRENT_TIMESTAMP-14  then 1 else 0  END) AS "2_4_sales_count",
("0_2_sales_count") - ("2_4_sales_count") as "load_volume_diff_0_2_2_4",
(("0_2_sales_count" - "2_4_weeks_load_volume")/"2_4_sales_count"::float) * 100  as "load_volume_diff_percent_0_2_2_4"
from sales 
group by cust_name;

我在“0_2_sales_count”和“2_4_sales_count”列中有不同客戶的零。 任何人都可以建議我如何處理上述錯誤。 我嘗試在 column = 0 時使用 case，但仍然出現相同的問題。

我正在使用 Amazon Redshift 數據庫。

謝謝

Answer 1

您可以使用案例檢查“2_4_sales_count”中的 0 並為每種情況使用正確的代碼

select cust_name,
      sum(case WHEN sale_date > CURRENT_TIMESTAMP-14 
          AND sale_date < CURRENT_TIMESTAMP then 1 else 0  END) AS "0_2_sales_count",
        sum(case WHEN sale_date > CURRENT_TIMESTAMP-28 
          AND sale_date < CURRENT_TIMESTAMP-14  then 1 else 0  END) AS "2_4_sales_count",
      ("0_2_sales_count") - ("2_4_sales_count") as "load_volume_diff_0_2_2_4",
      CASE WHEN "2_4_sales_count"::float = 0
          THEN 0 ELSE (("0_2_sales_count" - "2_4_weeks_load_volume")/"2_4_sales_count"::float) * 100  END as "load_volume_diff_percent_0_2_2_4"
from sales 
group by cust_name;

Answer 2

當 "2_4_sales_count"::float =0 then 1 end 時，嘗試使用 case

select cust_name,
sum(case WHEN sale_date > CURRENT_TIMESTAMP-14 AND sale_date < CURRENT_TIMESTAMP then 1 else 0  END) AS "0_2_sales_count",
sum(case WHEN sale_date > CURRENT_TIMESTAMP-28 AND sale_date < CURRENT_TIMESTAMP-14  then 1 else 0  END) AS "2_4_sales_count",
("0_2_sales_count") - ("2_4_sales_count") as "load_volume_diff_0_2_2_4",
(("0_2_sales_count" - "2_4_weeks_load_volume")/case when "2_4_sales_count"::float =0 then 1 end) * 100  as "load_volume_diff_percent_0_2_2_4"
from sales 
group by cust_name;

Answer 3

據推測，問題出在這一行：

(("0_2_sales_count" -"2_4_weeks_load_volume") / "2_4_sales_count"::float) * 100  as "load_volume_diff_percent_0_2_2_4"

我會這樣寫：

(("0_2_sales_count" - "2_4_weeks_load_volume") * 100.0 / nullif("2_4_sales_count", 0.0) as "load_volume_diff_percent_0_2_2_4"

除以零的最簡單解決方案是nullif() 。