PostgreSQL 的时间戳差异（以分钟为单位）

Question

我有以下查询：

Select works.id, works.client_id, COALESCE(TIMESTAMPDIFF(MINUTE,works.begin_at,works.finish_at), 0) / 60 * (clients.worker_cost_hourly * works.number_of_workers + works.machines *             clients.machine_cost_hourly) as cost
from works join clients on works.client_id = clients.id
where works.paid = 0

这对mysql工作正常，但postgresql抱怨TIMESTAMPDIFF ......有没有办法在两个 DBMS 中使用相同的查询实现这种行为？

顺便说一句， works.begin_at和works.finish_at被定义为time

Answer 1

您可以减去两次：这为您提供了一个间隔，您可以使用extract()将其转换为秒，然后使用算术将其转换为分钟：

extract(epoch from works.finish_at - works.begin_at) / 60

这将返回一个整数值。 如果你还想要小数部分，那么：

extract(epoch from works.finish_at - works.begin_at) / 60.0 

Answer 2

EXTRACT(EPOCH FROMworks.begin_at) - EXTRACT(EPOCH FROMworks.finish_at))/3600 给你小时差

Select works.id, works.client_id
, COALESCE(T(EXTRACT(EPOCH FROM works.begin_at) - EXTRACT(EPOCH FROM works.finish_at))/3600, 0) / 60 * (clients.worker_cost_hourly * works.number_of_workers 
+ works.machines * clients.machine_cost_hourly) as cost
from works join clients on works.client_id = clients.id
where works.paid = 0