For an instructor lead, in-depth look at learning SQL click below.
Welcome to this introductory blog post on SQL, the Standard Query Language for managing data in relational database management systems. If you’re just getting started with data analytics or want to strengthen your understanding of SQL, you’ve come to the right place. Let’s jump right into the basic building blocks of SQL.
What is SQL?
SQL (Structured Query Language) is a programming language used to communicate with and manipulate databases. To understand SQL, it helps to visualize a database as an Excel spreadsheet with numerous tables. SQL enables you to interact with the data in these tables in a variety of ways, such as retrieving, inserting, updating, and deleting records.
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-- For example, to retrieve all data from a table named 'Employee', the SQL code would look like this: SELECT * FROM Employee; |
SQL Syntax
Now, let’s dive deeper into the standard SQL commands, syntaxes, and examples.
1. SELECT
The SELECT statement is used to select data from a database. The data returned is stored in a result table. The syntax is:
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SELECT column1, column2, ... FROM table_name; |
Example
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-- This SQL statement selects the "FirstName" and "LastName" columns from the "Employees" table SELECT FirstName, LastName FROM Employees; |
2. WHERE
The WHERE clause is used to filter records. The WHERE clause is used to extract only those records that fulfill the specified condition. The syntax is:
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SELECT column1, column2, ... FROM table_name WHERE condition; |
Example
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-- This SQL statement selects all fields from "Employees" where the "Age" is greater than 30 SELECT * FROM Employees WHERE Age > 30; |
Practicing SQL Commands
We’ve just scraped the surface of SQL, but now you should have a basic understanding of what SQL is and some of its most common commands. The most effective way to learn SQL is to practice writing and executing SQL queries. If you’re eager to learn more, stay tuned for our upcoming posts.
Happy Querying!
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-- Your first SQL script SELECT 'Hello, SQL World!'; |