在BigQuery SQL中使用IF

Question

案例:我在BQ中有Sales表,而item_num列包含值1,-1和0.我想计算每个值有多少个案例.

尝试下面的一个简单的查询,但计数返回每个案件完全相同的数字..我缺少什么？

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

谢谢

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

甚至更简洁的版本:

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

这将给出如下结果

buysplus    buysminus   buyszero     
4           2           3

另一种选择是它的转置版本

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

结果如下

 buys        volume  
 0          3    
 1          4    
-1          2