Question

I need to select rows which are between the two null values.

My Question is that how can i get the names and marks of selected class which i need. I can’t change table everytime, because total number of rows in table is about 13000.

I think it’s too much and even more i am getting this table from excel file with some changes every time(twice a day or even more). What will be your opinion?

for example:-

Name       Marks
=================
class10    NULL
rahul      45
priti      65
terry      74
class9     NULL
Andrew     80
Nastya     75
Ajay       81
class8     NULL!

Answer 1

Your table has the wrong layout to serve your needs. There is no way to select rows “between values” in SQL, only if your table had an additional index that defines the order of the rows.

The correct table layout would be like this:

Class      Name       Marks
class10    rahul      45
class10    priti      65
class10    terry      74
class9     Andrew     80
class9     Nastya     75
class9     Ajay       81
...

Then you could query all members of class10 like this:

SELECT Name, Marks FROM table WHERE Class = 'class10'

Even better would be to make your own table for classes, but i doubt in your case of Excel-Import this would be desirable.

Hope this helps.

EDIT: Then import your excel table with an index so that it looks like this:

ID   Name       Marks
=====================
1    class10    NULL
2    rahul      45
3    priti      65
4    terry      74
5    class9     NULL
6    Andrew     80
7    Nastya     75
8    Ajay       81
9    class8     NULL!

Then you can select your marks of your class 10 like:

SELECT Name, Marks FROM table WHERE ID BETWEEN 2 AND 4

Or your class 9 like:

SELECT Name, Marks FROM table WHERE ID BETWEEN 6 AND 8

With a scripting language like PHP you could automate this task in a script.