Theory
In SQL, the SELECT statement is the most fundamental query used to retrieve data from a database. When you want to see everything contained within a specific table, you can use the asterisk (*) wildcard character as a shorthand to return all columns. This instructs the database to extract every single row and column without applying any filters or selections.
While the asterisk wildcard is an incredibly helpful shortcut for quickly exploring a new dataset and saving typing time, it is generally considered risky for production code. Using it in applications can slow down performance by retrieving unnecessary data and cause errors if the underlying table structure changes over time. However, for a Data Analyst doing initial data exploration, it is the perfect starting point to understand the data.
Task Scenario
Retrieve all information from the users table to get a high-level overview of the data we collect during onboarding.