How can I get row's index from a table in SQL Server?

You can use ROW.NUMBER

This is a example syntax for MySQL

SELECT  t1.toplistId, 
        @RankRow := @RankRow+ 1 AS Rank
FROM    toplist t1
JOIN    (SELECT @RankRow := 0) r;

This is a example syntax for MsSQL

SELECT ROW_NUMBER() OVER(ORDER BY YourColumn) AS Rank,TopListId
FROM TopList

ROW_NUMBER() MS SQL

Use in your code analytic functions