Subsection 1.3

What is SQL

~4 min

Reading

SQL stands for Structured Query Language.

Try this analogy

Think of SQL as asking a librarian

Imagine your team's data lives in a huge library. You need a specific answer : say, every contact who signed up at a survey event in March. You could spend hours walking shelf by shelf. Or you could walk up to the librarian and ask:

"Could you bring me every record where the source is 'survey' and the date is in March?"

SQL is how you ask that question. The librarian is the database. SELECT is "bring me," FROM is "from this section," and WHERE is "matching these conditions." The librarian doesn't care how big the library is. They go pull exactly what you asked for.

You will hear people pronounce it two common ways:

"Sequel."
"S-Q-L."

Both pronunciations are widely accepted. The choice often depends on where someone learned it, their organization, or their own preference.

SQL is the language people use to communicate with databases. Imagine a huge library with countless books. You need a specific answer, not a slow walk through every shelf. SQL lets you ask the library for exactly what you need.

In a database, the "books" are tables. The "shelves" are datasets. The "question" is a query.

SQL is designed to use readable words that look close to English. Common commands include:

SELECT: read columns from a table.
UPDATE: change existing records.
INSERT INTO: add new records.
DELETE FROM: remove records.

In this course, you will only use SELECT commands. That matters. SELECT reads data. It does not change the source table.

SQL can do many operations, including retrieving, filtering, sorting, summarizing, optimizing, and maintaining databases. For this course, we will stay focused on the core analyst workflow:

Get data.
Narrow it.
Sort it.
Count it.
Explain it.

Key terms

SQL: a language for asking questions of a database.
Database: an organized collection of data, usually arranged in tables.
Query: a SQL question that returns an answer.
Table: rows and columns of data, like a spreadsheet tab, but usually bigger and more structured.
Row: one record.
Column: one field or variable.

SQL also comes in different "flavors." Different database systems use SQL with their own features and syntax differences. Examples include MySQL, Oracle Database, Microsoft SQL Server, and Sybase/SAP ASE. The core ideas stay similar: commands like SELECT, INSERT, UPDATE, and DELETE work broadly the same way, but each system may have unique functions, extensions, or data types.

BigQuery is the SQL environment you will use here.

Learner action

Rewrite this sentence in your own words:

SQL is a language for databases.

Make it plain enough for a teammate who has never heard of SQL.

SQL stands for Structured Query Language. It is the language people use to talk to databases. Think of SQL as asking a huge library for exactly the books you need instead of searching shelf by shelf.

SQL commands use readable words like SELECT, UPDATE, INSERT INTO, and DELETE FROM. In this course you will only use SELECT commands, which read data but do not change it.

Key terms

SQL. A language for asking questions of a database.
Database. An organized collection of data, usually arranged in tables.
Query. A single SQL question and its answer.
Table. Rows and columns of data : like a tab in a spreadsheet, but typically much bigger.

Diagram 1.3 · Spreadsheet vs database vs SQL. Spreadsheets hold and edit small amounts of data. Databases hold large amounts. SQL is how you ask the database a precise question.

Rewrite in your own words

Write a one-sentence rewrite of: "SQL is a language for databases." Use plain language. Imagine you are explaining it to a teammate who has never heard of SQL.

SQL is just a language for asking questions of tables. Here's the smallest possible question: “how many voters do we have in this dataset?” Run a query that answers it.

Action: Write your one-sentence definition, then continue to the question-sorting activity.

Slide to complete