SQL

• SQL is a programming language used to interact with a DBMS (Database Management System).
• SQL lets you select, order, sum, and count data.
• SELECT and FROM are the two commands that appear in almost every query — SELECT says what columns you want, FROM says which table.
• WHERE filters rows based on a condition; AND / OR combine multiple conditions.
• Wildcards (* and %) let you match "everything" or "partial text" like names starting with a letter.
• ORDER BY sorts your results (ASC = ascending, DESC = descending).
• SUM adds up a numeric column; COUNT counts how many rows match.

Think of a database table like a giant spreadsheet sitting inside a piece of software called a DBMS (Database Management System) — think MySQL, Oracle, or Microsoft Access working behind the scenes. You can't just "look" at the spreadsheet and pick out rows by eye when it has millions of entries. Instead, you write a short, precise instruction in SQL, and the DBMS does the searching for you and hands back exactly what you asked for.

SQL stands for Structured Query Language. The word "structured" matters — SQL queries always follow a predictable shape (SELECT ... FROM ... WHERE ...), a bit like a sentence template. Once you know the template, you're just filling in the blanks with your own table and column names.

SQL allows a user to do four main things with data:

• Select data — pull out specific rows/columns
• Order data — sort the results
• Sum data — add up a numeric column
• Count data — count how many rows match

Every SQL query that retrieves data starts with these two commands working together. SELECT tells the DBMS which columns you want back. FROM tells it which table to look in. You genuinely cannot write one without the other for a basic query — SELECT on its own doesn't know where to look, and FROM on its own doesn't know what to return.

If you want every column in the table, you don't have to type each one out — you use the wildcard * to mean "all columns."

SELECT * FROM users;
-- retrieves ALL columns from the 'users' table

SELECT name, age
FROM users;
-- retrieves only the 'name' and 'age' columns