sql server的小题，请解答

Question

请问Compute是什么 后面的by是什么意思，不懂1. 假设表orderitem有列orderid(int类型)和列thenumber(int类型)，则下列语句可以正确执行的是（选一项）A、Select * from orderitem where orderid<=2 order by orderidCompute sum(thenumber) by orderidB、Select * from orderitem where orderid<=2Compute sum(thenumber) by orderidC、Select * from orderitem where orderid<=2 order by thenumberCompute sum(thenumber) by orderidD、Select * from orderitem where orderid<=2 order by orderidCompute sum(orderid) by thenumber 

Answer 1

这个就是order by;排序的意思，不过是有两个排序条件，例如A选项，先按照orderidCompute sum(thenumber)排序，如果结果中有数据这个值相同，那么就会再次按照  orderid排序；