For an instructor lead, in-depth look at learning SQL click below.
Welcome to the world of SQL! SQL (Structured Query Language) is a powerful tool primarily used for managing and manipulating data in relational databases. Whether you’re aspiring to become a data analyst, data scientist, database administrator, or even a back-end web developer, learning SQL can be a stepping stone in the right direction.
What is SQL?
SQL or Structured Query Language is used to communicate with and manipulate databases. It’s known for its simplicity while dealing with complex data structures and relations, which are the main features of Relational Databases.
The Basics of SQL
Tables and Columns
In SQL, data is stored in tables. Each table is made up of columns (fields) and rows (records). Here’s an example of how you might define a table of customers:
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CREATE TABLE Customers ( CustomerId int, FirstName varchar(255), LastName varchar(255), Email varchar(255), PhoneNumber varchar(15) ); |
Selecting Data
SQL lets you query, or ask for, the data you want from your tables. You can do this using the SELECT statement:
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SELECT * FROM Customers; |
This will return all the data from the Customers table. If you only wanted to get the first and last names, you would write:
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SELECT FirstName, LastName FROM Customers; |
Filtering Data
You can filter data using the WHERE clause:
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SELECT * FROM Customers WHERE FirstName = 'John'; |
This will return all customers whose first name is John.
Sorting Data
You can sort the results using the ORDER BY clause:
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SELECT * FROM Customers ORDER BY FirstName; |
This will return all customers, sorted alphabetically by their first name.
Conclusion
That was a quick ride through some of the basics of SQL! There’s still much more to explore including updating data, deleting data, and joining tables together. The best way to learn SQL is to practice, so get out there and start querying!