PostgreSQL中的时间分隔

Question

如何在PostgreSQL中运行以下查询（以下应该可以在MSSQL上运行）。目的是看多少时间拆开来伊文思发生了：

select ABS(CAST((a.timefield - b.timefield) as INT)) as 'Time Apart' 
from a inner join b on (a.id = b.id); 

Answer 1

根据“a.timefield”和“b.timefield”的类型，这应该工作：

SELECT ABS(EXTRACT(EPOCH FROM (a.timefield - b.timefield))) AS "Time Apart" FROM a INNER JOIN b ON (a.id = b.id); 

Answer 2

 
SELECT a.timefield - b.timefield 
FROM a 
    INNER JOIN B on (a.id = b.id) 

会给你一个区间数据类型