select cast( floor(rand()*N) as bigint) --可以获得成0至N之间任一整数;
select cast( ceiling(rand()*N) as bigint) --可以获得1至N之间任一整数;
select cast(rand() * (N1-N2) + N2 as bigint) --可以获得N1(含N1)至N2之间任一整数,N1和N2大小顺序不限。
select cast( floor(rand()*N) as bigint) --可以获得成0至N之间任一整数;
select cast( ceiling(rand()*N) as bigint) --可以获得1至N之间任一整数;
select cast(rand() * (N1-N2) + N2 as bigint) --可以获得N1(含N1)至N2之间任一整数,N1和N2大小顺序不限。