What is a Table Scan (Operator number 1)?
Before we try to understand table scan operator let’s try to see how can we see a SQL plan. Once you are in your SQL management studio, click on new query and write the SQL for which you want to see the SQL plan. Click on the icon which is displayed on the query window as shown below. Once you hit the icon you will see the query plan. Now that we have understood how to see a query plan let try to understand the first basic operator i.e. table scan. In order to understand the same we have created a simple companies table with company code and description. Do not create any primary key or indexes. Now write a simple SQL with a select clause on one of the properties, we have selected company code currently as shown in the above figure. If you hit on the query plan icon you will see table scan in your query plan. Now let’s try to understand what it signifies. If there is a primary key table scan operator scans row by row every record until it finds the exact record. For instance in our sea
