Are your current skills not enough to get you where you want to be in your career? Most probably, each person's answer is yes. Due to this thought, many professional developers enroll and learn the new skills and languages that help them grow in their careers.
One key point is embracing the fact that the product you are selling your clients is not the travel tours. There are certainly other businesses that sell travel tours for students or otherwise. But what makes your clients come to you and not a competitor is the technological aspect of the business. Having a good online presence is important. User satisfaction is the main thing that separates a successful product from a non-successful one.
The idea is to perform data cleansing on the Date and Time field from different formats into a unify format such as: YYYYMMDD. Here is a sample data to be used for the data cleansing that I will perform below...
SQL 2012 or higher - Processing hundreds of millions records can be done in less than an hour. Processing hundreds of millions of records requires a different strategy and the implementation should be different compared to smaller tables with only several millions of records.