Score表：
--首先计算总人数：
declare @count2 int =(select COUNT(*)from Score)--然后计算英语不及格人数：
declare @loster int=(select COUNT(*)from Score where english<60)
declare @harfcount int=floor(@count2/2)
while @harfcount<@loster
begin
update Score set english=english+2 where english<60
set @loster=(select COUNT(*)from Score where english<60)
end