What are Indexes in SQL? Indexes in SQL are like the "Index" page in a book. They hold the information about the various chapters present in the book along with their page numbers. Whenever we need to go to a particular chapter, we look for that chapter in Index, take its page number and directly jump to that page. Similarly, in databases also, we can think of the tables as huge books, with each row as a new chapter. The tables in databases can be enormous with lakhs and lakhs of rows and finding a particular row as per our need not only becomes hard but also impossible after an extend. Thus, to overcome this issue a simple concept of Indexing is used. These indexes help us in finding the exact row within a matter of seconds no matter how huge our table is. Thus, using a simple concept taken from our books to our database, we can significantly reduce the time a query takes to get the desired result set.