You have a Studets table as follows. The student table doesn't contains SlNo. You need to create a reoprt with SlNo. Write a query that add SlNo with the result set.
The student Master table is :

StuID SName Marks
S001 Naga 98
S102 Sundar 92
S203 Ganesh 95
S158 John 85
S211 Kumar 90

Answer:

We need to use Row_Number() function to obtain the result. Row_Number() gives the sequential number of a row within a partition of a result set, starting at 1 for the first row in each partition. The query is

  SELECT ROW_NUMBER() OVER (ORDER BY StuID ASC) AS 'SlNo' ,* from StudentMaster

I used order by with StudentID. So student id gets ordered in ascending at first and then RowNumber() function will be implemented on the result set.

The output will be

SlNo  StuID   SName   Marks

 1      S001    Naga       98 

 2      S102    Sundar    92

 3      S158    John       85

 4      S203    Ganesh    95

 5      S211    Kumar     90