英语翻译select * from a order by decode(a.xx,50,1,-1)desc

decode(a.xx,50,1,-1)是判断a.xx是否等于50,如果等于50,该函数取值为1,否则取值为-1.根据此函数的值进行倒序排列后,会优先显示值为1(也就是a.xx==50)的记录.