Introduction to SQL

Introduction to SQL

Here you can access the books table used in the course.

Note: When using sample integrations such as those that contain course data, you have read-only access. You can run queries, but cannot make any changes such as adding, deleting, or modifying the data (e.g., creating tables, views, etc.).

Take Notes

Add notes about the concepts you've learned and SQL cells with queries you want to keep.

A string is a sequence of letters or panctuanctions Storing short strings in a small data type like this saves storage space. Integer data types store whole numbers Float data types store numbers that include a fractional part, such as the 2-point-05 dollars that one patron, Jasmin, owes in fines.

Database schemas show data types for each field in all tables, and they also show relationships between tables. Looking at a schema is an excellent way to get to know a new database

QUERYING The SELECT statement appears first, followed on the next line by the FROM statement. It's best practice to end the query with a semicolon to indicate that the query is complete.

VIEWS a view refers to a table that is the result of a saved SQL SELECT statement. Views are considered virtual tables, which means that the data a view contains is not generally stored in the database. Rather, it is the query code that is stored for future use. A benefit of this is that whenever the view is accessed, it automatically updates the query results to account for any updates to the underlying database. To create a view, we'll add a line of code before the SELECT statement: CREATE VIEW, then the name we'd like for the new view, then the AS keyword to assign the results of the query to the new view name.

COUNT(*) tells you how many records are in a table. However, if you want to count the number of non-missing values in a particular field, you can call COUNT() on just that field.

Add your notes here

Explore Datasets

Use the books table to explore the data and practice your skills!

• Select only the title column.
• Alias the title column as book_title.
• Select the distinct author names from the author column.
• Select all records from the table and limit your results to 10.