indexes

[Guest chitrasathiya]

what is the difference between idex and order by?what is the use of idexes?

[Prakash]

Hi Chitra,This is Prakash.I would like to resolve ur issue.when you create an index on the rows, it will give a number to those rows based on the blocks in which they are stored. Index sorts the records based on the blocks and assigns the unique number. Whenever you want to retrieve the records, then it will retrieve those records based on the unique numbers. It makes the retireval faster. And, If you retrieve the records using an 'order by' clause, then it will temporarily get the records from the database and sort those records. It is confined only to that query. If u want to get the same output again, then you have to use 'order by' clause again. Got it?But, if you create an index then it will be created internally. It would be permanant until u delete the index.I hope, I've made ur issue clear. If at all, you've any doubts in this answer or if this reply is wrong, then let me know please.Thanq so much.Prakash.