INSERT and SELECT basics

Last reviewed Jun 1, 2026 Content v20260601

Track mode

sql_sandbox

Means

SQL sandbox

Reading

~1 min

Level

beginner

This lesson

This lesson teaches INSERT and SELECT basics: the SQL patterns, schema habits, and query reasoning you need before advancing in MySQL.

Teams query INSERT and SELECT basics on every MySQL codebase—skipping it leaves gaps in debugging and data reviews.

You will apply INSERT and SELECT basics in contexts like: Web apps on shared hosting, ecommerce, and many startups’ first production DB.

Copy MySQL SQL into the mysql client, local MySQL/MariaDB, or DB Fiddle (MySQL dialect)—use DESCRIBE and EXPLAIN where lessons show them. The in-browser lab ships later; mysql client is the practice path now.

When you can explain the previous lesson's ideas without copying example queries verbatim.

Standard SQL INSERT/SELECT with MySQL conveniences: multi-row INSERT, INSERT … SELECT, and strict mode behavior.

Inserts

INSERT INTO products (sku, name, price) VALUES ('C3', 'Adapter', 5.99);

INSERT INTO products (sku, name, price) VALUES
  ('D4', 'Part', 1.00),
  ('E5', 'Part', 2.00);

Practice: Run on database practice in mysql client.

Select filters

SELECT id, sku, price FROM products WHERE price >= 10 ORDER BY price DESC LIMIT 5;

SQL mode

ONLY_FULL_GROUP_BY rejects invalid GROUP BY—enable in dev to match production strictness.

Important interview questions and answers

Q: Multi-row INSERT benefit?
A: Fewer round trips than many single-row inserts.
Q: ORDER BY without LIMIT?
A: Fine on small tables; dangerous on huge tables in exploration.

Self-check

Write INSERT for two rows at once.
Filter products with price at least 10.

Tip: Enable ONLY_FULL_GROUP_BY in dev to match MySQL 8 defaults.

Interview prep

Multi-row INSERT?: One statement, many value tuples—fewer round trips.
ONLY_FULL_GROUP_BY?: Rejects invalid GROUP BY selects in strict mode.

Discussion

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Starter discussion topics

ONLY_FULL_GROUP_BY?
Multi-row INSERT?

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