SOQL OFFSET:

SOQL OFFSET:
This is an example for offset usage in pagination.The controller looks like this
public with sharing class soql_offset_example {

   private integer counter=0;  //keeps track of the offset
   private integer list_size=20; //sets the page size or number of rows
   public integer total_size; //used to show user the total size of the list

   public soql_offset_example() {
   total_size = [select count() from Number__c]; //set the total size in the constructor
   }

   public Number__c[] getNumbers() {
      try {
         Number__c[] numbers = [select Number__c, Square_Root__c 
                                from Number__c 
                                order by Number__c 
                                limit :list_size 
                                offset :counter];

         return numbers;
      } catch (QueryException e) {
         ApexPages.addMessages(e);   
         return null;
      }
   }

   public PageReference Beginning() { //user clicked beginning
      counter = 0;
      return null;
   }

   public PageReference Previous() { //user clicked previous button
      counter -= list_size;
      return null;
   }

   public PageReference Next() { //user clicked next button
      counter += list_size;
      return null;
   }

   public PageReference End() { //user clicked end
      counter = total_size - math.mod(total_size, list_size);
      return null;
   }

   public Boolean getDisablePrevious() { 
      //this will disable the previous and beginning buttons
      if (counter>0) return false; else return true;
   }

   public Boolean getDisableNext() { //this will disable the next and end buttons
      if (counter + list_size < total_size) return false; else return true;
   }

   public Integer getTotal_size() {
      return total_size;
   }

   public Integer getPageNumber() {
      return counter/list_size + 1;
   }

   public Integer getTotalPages() {
      if (math.mod(total_size, list_size) > 0) {
         return total_size/list_size + 1;
      } else {
         return (total_size/list_size);
      }
   }
}

and the page looks like this

<apex:page title="Salesforce SOQL Offset Example Using Visualforce" controller="soql_offset_example" showHeader="false" sidebar="false" readOnly="true" cache="false">

<apex:sectionHeader subtitle="SOQL Offset Example" title="Square Root Table"/>

<apex:pageBlock >   
   <apex:pageBlockButtons location="top" >
   <apex:outputPanel id="myButtons">
   <apex:form >
        <apex:commandButton action="{!Beginning}" title="Beginning" value="<<" disabled="{!disablePrevious}" reRender="myPanel,myButtons"/>
        <apex:commandButton action="{!Previous}" title="Previous" value="<" disabled="{!disablePrevious}" reRender="myPanel,myButtons"/>        
        <apex:commandButton action="{!Next}" title="Next" value=">" disabled="{!disableNext}" reRender="myPanel,myButtons"/>
        <apex:commandButton action="{!End}" title="End" value=">>" disabled="{!disableNext}" reRender="myPanel,myButtons"/>        
   </apex:form>
   </apex:outputPanel>
   </apex:pageBlockButtons>

   <apex:pageBlockSection columns="1">
       <p>This Visualforce Page demonstrates the usage of the "OFFSET" clause in a SOQL SELECT statement.  You can "Paginate" through 
       a large result set quickly.  This example allows a user to paginate up and down through a result set 20 records at a time.  
       Using the "VCR" buttons above, you can also quickly skip to the end or the beginning of the set.</p>
       <p>The accompanying code can be viewed here:  <a href="http://blog.redpointsolutions.com/bid/182738/Add-Pagination-to-your-Visualforce-Pages-using-the-SOQL-OFFSET-Clause" target="_blank">RedPoint Solutions BLOG</a></p>
   </apex:pageBlockSection>
    
   <apex:pageBlockSection title="Numbers and their Square Roots (Total List Size: {!total_size})" collapsible="false">
   <apex:outputPanel id="myPanel">
   <apex:pageMessages id="theMessages" />
   <apex:pageBlockTable value="{!numbers}" var="n" align="center">
        <apex:column value="{!n.Number__c}" />
        <apex:column value="{!n.Square_Root__c}" />
        <apex:facet name="footer">Showing Page # {!pageNumber} of {!totalPages}</apex:facet>
   </apex:pageBlockTable>
   </apex:outputPanel>
   </apex:pageBlockSection>

</apex:pageBlock>

</apex:page>