SQL 查询 - 不为空

Question

我有sql查询：

Select id
    ,MAX(CASE WHEN (pos = "10") THEN date ELSE NULL END) position10
    ,MAX(CASE WHEN (pos = "18") THEN date ELSE NULL END) position18
    ,MAX(CASE WHEN (pos = "20") THEN date ELSE NULL END) position20
    
FROM table
WHERE 
date BETWEEN "${od=2021-05-01 00:00:01}" AND "${do=2021-07-01 00:00:01}"
AND pos IN('10','18','20')
group by id

我知道了 table

id	位置10	位置20	位置30
1	2021-05-02	2021-05-02	2021-05-3
2	2021-05-15	2021-05-16	2021-05-18
3	2021-07-08	空	空

而且我想要未提取 NULL 值的行。试试这个：

SELECT * FROM (
Select id
        ,MAX(CASE WHEN (pos = "10") THEN date ELSE NULL END) position10
        ,MAX(CASE WHEN (pos = "18") THEN date ELSE NULL END) position18
        ,MAX(CASE WHEN (pos = "20") THEN date ELSE NULL END) position20
        
    FROM table
    WHERE 
    date BETWEEN "${od=2021-05-01 00:00:01}" AND "${do=2021-07-01 00:00:01}"
    AND pos IN('10','18','20')
    group by id )T 
WHERE (position10 IS NOT NULL)
       OR (position18 IS NOT NULL)
       OR (position20 IS NOT NULL)

但它仍然为我选择 NULL 值出现在某处的位置。

Answer 1

您需要将 WHERE 子句中的 OR 更改为 AND

SELECT * FROM (
Select id
        ,MAX(CASE WHEN (pos = "10") THEN date ELSE NULL END) position10
        ,MAX(CASE WHEN (pos = "18") THEN date ELSE NULL END) position18
        ,MAX(CASE WHEN (pos = "20") THEN date ELSE NULL END) position20
        
    FROM table
    WHERE 
    date BETWEEN "${od=2021-05-01 00:00:01}" AND "${do=2021-07-01 00:00:01}"
    AND pos IN('10','18','20')
    group by id )T 
WHERE position10 IS NOT NULL
       AND position18 IS NOT NULL
       AND position20 IS NOT NULL

SQL 查询 - 不为空

SQL query - not null

sql

impala