In SQL Basics we’ll take a look at what databases are and how you can retrieve information from them. Databases can store massive amounts of information to be retrieved at a later date. Databases act as the memory for dynamic web sites or mobile apps.
https://teamtreehouse.com/library/sql-basics
Building off of previous SQL courses, this course will begin to introduce the student to more complex database concepts. Students will learn to think about data as sets and subsets and practice achieving desired query results via such operations as inner and outer joins, unions and except. They will also be introduced to the concepts of Set Theory and Database Normalization to aid in understanding good query practices.
-What is a Relational Database?
-Database Normalization
-Database Keys
-Table Relationships
-Set Operations
In this stage, we will explore what a relational database is, why we structure databases in this way, and talk a little bit about the benefits relational databases. Why We Make Databases "Relational"
-Database Normalization
-How Normalization Helps Us
-Database Normalization Review
-Set Theory and Relational Databases
-Theoretical Groundwork
-Set Theory Review
In this stage, we introduce the concept of "Keys." Without Keys, databases as we know them would not be able to function.-Unique Keys
-Primary Keys
-Database Keys Review
-Foreign Keys
-Foreign Keys Review
Relationships in databases help us to describe the way that one tables links or relates to another.-One to Many Relationships
-Many to Many Relationships
-One to One Relationships
-Modeling Table Relationships
-Table Relationships Review
We will be transitioning from mostly theoretical concepts to hands-on application of the concepts we’ve covered in the previous three stages. We will see how to use table relationships to produce query results that combine data from multiple tables.-Join Queries
-Inner Joins
-Outer Joins
-Review: Table Joins
-Review and Practice
-JOIN Queries (Quiz)
are one of the most advanced concepts to learn in SQL query writing. Seeing lots of examples and getting lots of practice will help solidify the concept.-What are Set Operations?
-Union Operations
-Union All Operations
-Intersect Operations
-Except Operations
-Set Operations Review 5 questions
-Review and Practice
-Set Operations(Quiz)
As you begin using subqueries, be advised that a poorly structured subquery written against a large table or tables can impact overall query performance. Be careful if you are writing subqueries against data sets that consume tables with row counts in the million-plus row range.
This course does not cover the concept called Correlated Subqueries, which are slightly different in how they tie in with the outer query. Most of the time a regular subquery will do what you need, but correlated subqueries can be handy, too. These are especially heavy weight on the database engine, as they run the subquery many times; once per row in the outer query.Information on all subquery types including correlated subqueries
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