在BigQuery中使用IF

Question

案例：我在BQ中有Sales表，item_num列包含值1，-1和0.我想統計每個值有多少個案例。

在下面嘗試了一個簡單的查詢，但計數返回完全相同的數字爲每個案件..我缺少什麼？

SELECT 
count(if(item_num > 0,1, 0)) as buysplus, 
count(if(item_num < 0,1, 0)) as buysminus, 
count(if(item_num = 0,1, 0)) as buyszero 
from MyShop.Sales 

感謝

Answer 1

SELECT 
    SUM(IF(item_num > 0, 1, 0)) AS buysplus, 
    SUM(IF(item_num < 0, 1, 0)) AS buysminus, 
    SUM(IF(item_num = 0, 1, 0)) AS buyszero 
FROM MyShop.Sales 

，甚至它少verbous版本：

SELECT 
    SUM(item_num > 0) AS buysplus, 
    SUM(item_num < 0) AS buysminus, 
    SUM(item_num = 0) AS buyszero 
FROM MyShop.Sales 

這會給喲結果類似下面

buysplus buysminus buyszero  
4   2   3 

另一種辦法是調換版本它是

SELECT 
    item_num AS buys, 
    COUNT(1) AS volume 
FROM MyShop.Sales 
GROUP BY 1 

，結果如下

buys  volume 
0   3  
1   4  
-1   2