SQL Structured Query Language

SQL (Structured Query Language) is a standard language used to communicate with and manipulate databases. Here are the fundamental ```sql commands

SELECT

Purpose: Used to retrieve data from a database.

Syntax

SELECT column1, column2, ...
FROM table_name;

SELECT Name, Score
FROM Students;

FROM

Purpose: Specifies the table from which to retrieve data.

Syntax

SELECT column1, column2, ...
FROM table_name;

WHERE

Purpose: Filters records to only include those that meet a specified condition.

Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition;

SELECT Name, Score
FROM Students
WHERE Score > 80;

Using SQL to Search for Data

SQL is highly effective for searching and filtering data based on specific criteria.

To find students with scores above 85:

SELECT Name, Score
FROM Students
WHERE Score > 85;

This command will return all records from the Students table where the Score is greater than 85.

Using * to Search for Data

To find all students fields you can use the * command

SELECT *
FROM Students
WHERE Score > 85;

This command will return all records from the Students table where the Score is greater than 85 and include all fields in the returned data set.

Using = to Search for Data

To find all students fields you can use the * command

SELECT *
FROM Students
WHERE Score = 85;

This command will return all records from the Students table where the Score is equal to 85 and include all fields in the returned data set.

Key Points

SELECT: Retrieve specific columns from a table.
FROM: Specify the table to retrieve data from.
WHERE: Apply conditions to filter the results.

SQL provides a powerful way to query and manipulate data in relational databases, making it an essential tool for database management and data analysis.

Practical Practice

Use the W3Schools website to pratice SQL

Try putting in the following examples

SELECT * 
FROM Customers
Where Country="Germany";

SELECT CustomerName
FROM Customers
Where Country="Germany";

SELECT ProductName, Price
FROM Products
Where Price<20;