What is the basic difference between clustered and a non-clustered index?

clustered index arrange data in physical order while non clustered index arrange data in logical order. in a table we have only one clustered index but we can hav more then one non clustered index clustered index contain a key and row data while non clustered index contain key and a pointer to row we can create clu index on single column but we can create non clus index on multiple column clustered index is use when column value are unique but it is not necessary in non clus index

Clustered index arranged in physically order, while Non-clustered index arranged in logical order only one clustered index reside in table, while More than one Non-clustered index reside in table. clustered index implement on only one column in table , but non clustered index can implement on one column or combitination of more than one column in table.

Clustered index arranged in physically order, while Non-clustered index arranged in logical order only one clustered index reside in table, while More than one Non-clustered index reside in table. clustered index implement on only one column in table , but non clustered index can implement on one column or combitination of more than one column in table.

clustered index arranges the data physically whereas Non Clustered index arrange the data logically. that's why Clustered index can be only one in a table while Non-Clustered index might be more than one.

Clustered indexes sort and store the data rows in the table or view based on their key values. A nonclustered index contains the nonclustered index key values and each key value entry has a pointer to the data row that contains the key value. Source : http://msdn.microsoft.com/en-IN/library/ms190457.aspx