getting specific index from sql - sql

Question

I'm trying to pull from my sql database without having to load it into a var and pulling the items I want with a for loop.
How can I get the 5 items in the 5th index
" " 5 " " 10th index...
This is what I'm doing not it's way to hackish.
function get_db(a) {
index_count=a
db.transaction(
function(tx) {
var rs = tx.executeSql('SELECT * FROM Greeting');
var r=""
if (up_check === 0){
index_count = index_count +4
}
r += rs.rows.item(index_count).salutation + ": " + rs.rows.item(index_count).salutee + "\t\t"
})
return r
}
I'd ideally want to get something like
var rs = tx.executeSql('SELECT * FROM index_count (and the next for items) Greeting');

Answer 1

If you're SQL Server 2005 or above you can use ROW_NUMBER().
Something like this (freehand):
SELECT *, ROW_NUMBER() OVER(ORDER BY [youordercolumns]) AS [RowNum]
FROM [youtable]
WHERE [RowNum] BETWEEN #index AND #index + 4

Answer 2

It really depends on what Database Server you are using.
For example, MySQL supports a very simple but non-standard solution:
SELECT * FROM Greeting
LIMIT 5 OFFSET yourStartingIndex
Other servers support one or more ways of performing a 'limit with offset'.
The SQL standard provides three ways:
Using OFFSET and FETCH FIRST:(since SQL:2008)
SELECT *
FROM Greeting
OFFSET yourStartingIndex ROWS
FETCH FIRST 5 ROWS ONLY
Using a Window function:(since SQL:2003)
SELECT * FROM (
SELECT
ROW_NUMBER() OVER (ORDER BY YourOrderColumns ASC) AS rownum,
columns
FROM tablename
) AS foo
WHERE rownum > yourStartingIndex AND rownum <= (4+yourStartingIndex)
Using a cursor:
DECLARE cursor-name CURSOR FOR ...
OPEN cursor-name
FETCH RELATIVE number-of-rows-to-skip ...
CLOSE cursor-name
LINKS: http://troels.arvin.dk/db/rdbms/#select-limit-offset