For an instructor lead, in-depth look at learning SQL click below.
Welcome to the SQL Crash Course! In this post, we’ll be introducing Structured Query Language, or SQL. SQL is a powerful language used in programming and designed for managing data held in a relational database management system (RDBMS), or for stream processing in a relational data stream management system (RDSMS).
Introduction to SQL
It is not an exaggeration to say that SQL is one of the most important skills for any data professional. As a standard language for managing and manipulating databases, it is used daily by database administrators, data analysts, and developers. In this guide, we’ll give you a quick crash course to help you get started with SQL.
SQL Query Structure
SQL code is usually built around statements. Each statement carries a specific SQL command, like ‘SELECT’, ‘INSERT’, ‘UPDATE’, etc. Each command tells the database to perform a certain operation.
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/* This is how a simple SQL SELECT statement looks like Here we're fetching all the data from a table named 'students' */ SELECT * FROM students |
SELECT Statement
The code above is an example of the SELECT statement. SELECT is used to query data from a database. The * symbol indicates that we’re querying all columns from the table.
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/* This is how a simple SQL SELECT statement looks like when you want specific columns Here we're fetching only 'first_name' and 'last_name' from a table named 'students' */ SELECT first_name, last_name FROM students |
WHERE Clause
SQL isn’t just about pulling all data from a database, you can pull specific data based on certain conditions with the WHERE clause.
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/* Here we're fetching the 'first_name' and 'last_name' columns from the 'students' table for the students who have a 'pending' status. */ SELECT first_name, last_name FROM students WHERE status='pending' |
CONCLUSION
This post only covers a small portion of what SQL can do. There is much more to the language, including updating data, deleting data, creating and modifying tables, managing database schemas, and much more. Practice is key in becoming proficient at SQL, so always spend some time writing SQL queries to be more proficient! Happy learning!
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/* Fetch data, perfect your skills, and keep exploring the power of SQL! */ SELECT * FROM learning |