MySQL

SELECT TIMESTAMPDIFF(HOUR, '2023-10-01 12:00:00', '2023-10-02 15:30:00') AS hours_difference;

PostgreSQL

//EXTRACT(EPOCH FROM ('2023-10-02 15:30:00'::timestamp - '2023-10-01 12:00:00'::timestamp))
// 获取的是两个时间相差的秒数，在此基础上除3600获取相差的小时数，或者进行其他计算
SELECT EXTRACT(EPOCH FROM ('2023-10-02 15:30:00'::timestamp - '2023-10-01 12:00:00'::timestamp)) / 3600 AS hours_difference;

SQL Server

SELECT DATEDIFF(HOUR, '2023-10-01 12:00:00', '2023-10-02 15:30:00') AS hours_difference;

postgres sql 时间

----条件为时间的小时数除三余二
where cast(to_char("2024-10-22 13:00:00", 'HH24') as INTEGER) % 3 = 2