What is SQL? | BUS 104 – SQL Exam

Still feeling nervous for your exam? Check out the SQL Cram Kit for practice questions that emulate the difficulty that you'll face on your exam. Each question includes a thorough step-by-step explanation where I walk you through the entire problem solving process!

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SQL explained

As defined by W3Schools, a world-renowned web developer site...

SQL (Structured Query Language) is a standard language for accessing and manipulating databases.

SQL is a coding language used to interact with databases through the use of queries.

Picture this: a doctor’s office with a filing cabinet in the left corner containing relevant information to the office’s operation.

Doctor's office with filing cabinet identified on left

The filing cabinet has 3 drawers: Appointments, Clients, and Staff.

The Appointments, Clients, and Staff cabinets identified on filing cabinet

Each drawer contains papers with the same required information on each paper.

For example, each paper in the Appointments drawer contains (1) the date and time of the appointment, (2) the name of the client, (3) the name of the doctor, and (4) a description of the appointment.

The main components of SQL are databases, tables, and records.

In comparison to the doctor's office, the filing cabinet is the database. Each drawer is a table. Each paper is a record.

The entire cabinet is the database. Each cabinet is a table. Every paper in each cabinet is a record.

"A doctor’s office with a filing cabinet containing relevant information to the office’s operation." This is the database.

"The filing cabinet has 3 drawers: Appointments, Clients, and Staff." These are the tables.

"Each drawer contains papers with the same required information on each paper." These are the records.

"For example, each paper in the Appointments drawer contains (1) the date and time of the appointment, (2) the name of the client, (3) the name of the doctor, and (4) a description of the appointment." These are the fields of the Appointments table. Fields are essentially the columns of information contained in a table.

Attributes are essential the specific values that each record contains corresponding to the table's fields.

Think of fields as table specific. Each table has fields, or columns, like the date and time of the appointment, the name of the client, the name of the doctor, and a description of the appointment.

Think of attributes as record specific. Each record has attributes, or values, for the columns corresponding to date and time of the appointment, the name of the client, the name of the doctor, and a description of the appointment.

Whenever an employee goes into the office to createreadupdate, or delete information from the filing cabinet, they are executing a query.

Now that you've got a conceptual understanding of how SQL works, let's start coding! Click SELECT & FROM below to learn the core statements of any SQL query!

Concepts

Each exam concept broken down with relatable situations to your life!

ToolsSQL Follow-along Guide (FREE)
LessonWhat is SQL?
LessonSELECT & FROM
LessonJOIN
LessonWHERE
LessonGROUP BY
LessonHAVING
LessonORDER BY
LessonTroubleshooting errors

Practice Problems

Include step-by-step explanations through each part of the problem!

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October 29, 2020

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