如何计算 BigQuery 中每个 ID 列值的出现次数

Question

如果我在 BigQuery 中有一个这样的表

id    success
-------------
01    true
01    true
02    false
02    true

我想以此结束：

id    true    false
--------------------
01    2       0  
02    1       1  

我已经得到了这个，但我想知道是否有更优雅的方法来做到这一点？

SELECT 
    t1.id,
    (
        SELECT 
            count(*)
        FROM `my_table` t2
        WHERE t2.success = true and t2.id = t1.id
    ) as trueCount,
    (
        SELECT 
            count(*)
        FROM `my_table` t3
        WHERE t3.success = false and t3.id = t1.id
    ) as falseCount
FROM `my_table` t1
GROUP BY id

Answer 1

考虑条件聚合，它应该适用于几乎所有数据库：

SELECT 
    t.id,
    SUM(CASE WHEN t.success = true THEN 1 ELSE 0 END) AS trueCount,
    SUM(CASE WHEN t.success = false THEN 1 ELSE 0 END) AS falseCount
FROM `my_table` t
GROUP BY t.id