按非唯一列选择顶部语句的排序

Question

I have two sql queries

select * from table1
ORDER BY column1

Select top 10 * from table1
ORDER by column1

Column1 is a non unique column and table1 does not have a primary key.

When I run both queries, I'm getting the rows returning in different orders. I attribute this to the fact that the criterion for ranking (the Order By) is non unique.

I'm wondering what method does a normal SELECT statement use to determine the output order of the rows in this case and what a select top statement would use. Is it just random?

Answer 1

In the non-unique case, the output order of the rows should not be relied upon.

Instead, impose the ordering you want (by including other columns in the ORDER BY)

Answer 2

认为它是随机的-即使在某些情况下它不是随机的，如果联系少于ORDER BY要求的排序，则DBMS也不应该对结果的排序作出保证。