Chapter 14 Conclusion
Throughout this chapter, we delved deep into SQL queries, exploring their potential and their role in organizing, manipulating, and extracting information from databases.
We started by expanding our knowledge of SELECT queries, learning to use subqueries, EXISTS, ANY, ALL, and CASE statements to create more complex and powerful queries. We saw how subqueries allow us to perform operations using the data derived from another SELECT statement, providing the ability to solve more intricate problems.
From there, we explored JOIN operations, which enable us to combine rows from two or more tables based on a related column. We learned the syntax of various types of JOINs: INNER JOIN, LEFT (OUTER) JOIN, RIGHT (OUTER) JOIN, and FULL (OUTER) JOIN, and discussed their use-cases.
Finally, we introduced aggregate functions, which perform a calculation on a set of values and return a single value. We learned about SUM(), AVG(), COUNT(), MAX(), and MIN(), and discussed GROUP...