Seek & Scan in SQL Server

Question

After googling i came to know that Index seek is better than scan.

How can I write the query that will yield to seek instead of scan. I am trying to find this in google but as of now no luck.

Any simple example with explanation will be appreciated.

Thanks

Answer 1

1. Search by the primary key column(s)
2. Search by column(s) with index(es) on them

An index is a data structure that improves the speed of data retrieval operations on a database table. Most dbs automatically create an index when a primary key is defined for a table. SQL Server creates an index for primary key (composite or otherwise) as a "clustered index", but it doesn't have to be the primary key - it can be other columns.

NOTE:

• LIKE '%'+ criteria +'%' will not use an index; LIKE criteria +'%' will

Related reading:

• SQL SERVER – Index Seek vs. Index Scan
• Index
• Which is better: Bookmark/Key Lookup or Index Scan