If we would like to make execution of SQL declarations to speedy then table index can help it out. Here is the structure of making an index;
For example, we have a table;
If we have to form an index for First Name column, then the syntax will be;
on Purchaser (First_Name)
For making an index on Address and City column, we will write the following syntax;
on Purchaser (Address, City)
It is a lenient way of making index on different columns. The simple way is to write IDX in front of the name of an index.
The way of creating index in all databases is not same. So, you have to know the syntax of the specific database which you are using.