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Structured Query Language (SQL) is a primary tool for database management. It allows you to access and manipulate databases. But for beginners, SQL might seem intimidating. This post aims at simplifying SQL and making its core concepts easier to understand.
What is SQL?
SQL stands for Structured Query Language. It’s a standard programming language specifically designed for managing data held in a Relational Database Management System (RDBMS). It has a variety of applications such as adding and updating data in the database, retrieval of data, and the creation and modification of schemas.
SQL Statements
At the foundation of SQL are the SQL statements. These statements enable you to perform tasks such as updating data on a database or retrieving data from a database. Some common examples of SQL statements include:
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-- SELECT statement SELECT * FROM Employees; -- INSERT statement INSERT INTO Employees (FirstName, LastName, Age, Address) VALUES ('John', 'Doe', 30, '123 4th Ave'); -- UPDATE statement UPDATE Employees SET Age=40 WHERE FirstName='John' AND LastName='Doe'; -- DELETE statement DELETE FROM Employees WHERE FirstName='John' AND LastName='Doe'; |
SELECT Statement
The SELECT statement is used to select data from a database. The data returned is in a result table called the result-set. The simple syntax of the SELECT Statement:
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SELECT column1, column2, column3, ...; FROM table_name; |
INSERT INTO Statement
The INSERT INTO statement is used to insert new rows in a database. The simple syntax of the INSERT Statement:
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INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...); |
UPDATE Statement
The UPDATE statement is used to modify the existing records in a database. The simple syntax of the UPDATE Statement:
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UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition; |
DELETE Statement
The DELETE statement is used to delete existing records in a database. The simple syntax of the DELETE Statement:
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DELETE FROM table_name WHERE condition; |
Conclusion
By mastering these four fundamental SQL statements, you’ll be able to conduct a significant amount of database operations. Remember, the key to learning SQL is practice. So, take some time to familiarize yourself with these commands and try to utilize them in real scenarios.