Paging with Oracle and sql server and generic paging method

Question

I want to implement paging in a gridview or in an html table which I will fill using ajax. How should I write queries to support paging? For example if pagesize is 20 and wh

Answer 1

Unfortunately, the methods for restricting the range of rows returned by a query vary from one DBMS to another: Oracle uses ROWNUM (see ocdecio's answer), but ROWNUM won't work in SQL Server.

Perhaps you can encapsulate these differences with a function that takes a given SQL statement and first and last row numbers and generates the appropriate paginatd SQL for the target DBMS - i.e. something like:

sql = paginated ('select empno, ename from emp where job = ?', 101, 150)

which would return

'select * from (select v.*, ROWNUM rn from ('
 + theSql
 + ') v where rownum < 150) where rn >= 101'

for Oracle and something else for SQL Server.

However, note that the Oracle solution is adding a new column RN to the results that you'll need to deal with.