In the previous chapters, you learned the basics of data analysis and SQL. You learned how to use
DROP SQL statements to apply create, read, update, and delete (CRUD) operations on a table. These techniques are the foundation for data analytics.
However, in the real world, as a data analyst, you usually do not handle the entire CRUD flow. To be more specific, you usually do not create datasets from scratch. You will receive data from outside sources. This data is usually in a form that would not fit your needs perfectly and you would need to perform some transform operations to make the data usable. One such operation is the creation of clean datasets from existing raw datasets. The raw data may be missing some information, contain information that is not in the format that fits your needs, or contains information that may not be accurate.
According to Forbes, it is estimated that almost 80% of the time spent...