title: Which is faster insert query or update in sql?
body: <p>In my app,I have a requirement to insert 600 rows and each row have 10 parameters that means I am inserting 6000 data for every 5 seconds.So I am deleting the previous value and inserting 600 rows for every 5 seconds.The other way is I can update the previous data using where Clause.So wondering to know which will have least performance issue.Also if I have some millions of rows and If i want to select the data for ID 50000.Then I will write this way</p>
  
  <pre><code>select * from mytable where ID=50000.
  </code></pre>
  
  <p>After some time If i need the data for id 90000 then Will the sql server search from beginning ID(ID=1) for every select statement or it will directly move to ID=90000
  My query is will sql server starts looking from id=1 till it matches the where clause or how it searches?</p>
  
  <p><strong>EDIT</strong> ID is Primay key and auto increment</p>