Question

我希望使用postgresql从开始时间戳开始每3分钟选择一次表中的数据。

31-12-2015 10:00:00
31-12-2015 10:01:00
31-12-2015 10:02:00
31-12-2015 10:03:00
31-12-2015 10:04:00
31-12-2015 10:05:00

必需输出

31-12-2015 10:00:00
31-12-2015 10:03:00

Answer 1

使用样本表

CREATE TABLE tm (tme TIMESTAMP);

INSERT INTO tm
VALUES ('31-12-2015 10:00:00')
    ,('31-12-2015 10:01:00')
    ,('31-12-2015 10:02:00')
    ,('31-12-2015 10:03:00')
    ,('31-12-2015 10:04:00')
    ,('31-12-2015 10:05:00');

并且选择应该是

SELECT *
FROM tm
WHERE to_char(tme, 'MI')::INT IN (
        SELECT *
        FROM (
            SELECT to_char(tme, 'MI')::INT col
            FROM tm
            ) t
        WHERE mod(col, 3) = 0
        );

简化

select * 
from
tm where mod(to_char(tme, 'MI')::int,3)=0

结果：

tme                 
------------------- 
2015-12-31 10:00:00 
2015-12-31 10:03:00

DEMO

从开始时间戳开始每3分钟选择一次数据

1 个答案: