我有以下查询,详细讨论了here:
select
t1.session,t1.center center1,t2.center center2,t1.performance - t2.performance performance
from mytable t1
inner join mytable t2
on t1.session = t2.session
WHERE t1.performance = (SELECT MAX(performance)
FROM mytable t3 WHERE t3.session = t1.session)
AND t2.performance = (SELECT MIN(performance)
FROM mytable t3 WHERE t3.session = t2.session)
现在,mytable
本身是一个非常长的查询(超过一页)。我想知道是否有任何方法可以使用一些常量定义查询(我们通常在Java或C ++中这样做),以避免一次又一次地复制粘贴相同的行。