SQL 特定的 WHERE 子句

Question

我是 SQL 新手，正在尝试组织一些具有特定限制的棒球数据。

我得到了当天的数据，局，投手的投手，以及是在局的顶部还是底部。

有没有一种方法可以有效地查询系统，只有当一局投手有一个单一的投手时我才会取回数据？

|-----------------------------------|
| day | inning | pitcher| top_bottom|
|  1       1        AE1      top    |
|  1       1        AE1      top    |
|  1       1        AE1      top    |
|  1       2        AE1      top    |
|  1       2        AE1      top    |
|  1       2        AE2      top    |
|-----------------------------------|

结果将是前 3 排，因为在每场比赛中投手都是 AE1，而我不会得到后三排，因为投手 AE1 和 AE2 都在所述局投球。

Answer 1

您可以按每一inning您的数据进行分组，并且只inning那些只有一个不同投手的组：

select inning, max(pitcher) as pitcher
from your_table
where day = 1
group by inning
having count(distinct pitcher) = 1

如果您需要完整的记录而不仅仅是 2 列，那么您可以执行以下操作：

select * 
from your_table
where inning in 
(
  select inning
  from your_table
  where day = 1
  group by inning
  having count(distinct pitcher) = 1
)

Answer 2

您可以考虑以下几点：

DROP TABLE IF EXISTS my_table;

CREATE TABLE my_table
(id SERIAL PRIMARY KEY
,inning INT NOT NULL
,pitcher CHAR(3) NOT NULL
);

INSERT INTO my_table VALUES
(1,1,'AE1'),
(2,1,'AE1'),
(3,1,'AE1'),
(4,2,'AE1'),
(5,2,'AE1'),
(6,2,'AE2');

SELECT DISTINCT x.* 
           FROM my_table x 
           LEFT 
           JOIN my_table y 
             ON y.inning = x.inning 
            AND y.pitcher <> x.pitcher 
            AND y.id <> x.id 
          WHERE y.id IS NULL;
+----+--------+---------+
| id | inning | pitcher |
+----+--------+---------+
|  1 |      1 | AE1     |
|  2 |      1 | AE1     |
|  3 |      1 | AE1     |
+----+--------+---------+
3 rows in set (0.00 sec)

Answer 3

在 BigQuery 中，您可以使用：

select as value any(t)
from t
group by t.inning
having min(pitcher) = max(pitcher);

Answer 4

下面是 BigQuery 标准 SQL

#standardSQL
SELECT * EXCEPT(singular_pitcher)
FROM (
  SELECT *, 1 = COUNT(DISTINCT pitcher) OVER(PARTITION BY day, inning) singular_pitcher
  FROM `project.dataset.table`  t
)
WHERE singular_pitcher