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

这对于mysql来说很好，但是postgresql抱怨TIMESTAMPDIFF ...是否可以通过相同的查询在两个DBMS中实现这种行为？

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。如果还需要小数部分，则：

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

Answer 2

EXTRACT（EPOCH FROM works.begin_at）-EXTRACT（EPOCH FROM works.finish_at））/ 3600为您提供时差

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