MySQL vs PostgreSQL vs SQLite - Visual Side-by-Side Comparison

Concept Flow - MySQL vs PostgreSQL vs SQLite

Choose Database Type

↓

Pick based on needs

This flow shows choosing between MySQL, PostgreSQL, and SQLite based on their main features and use cases.

Execution Sample

MySQL

SELECT VERSION();
-- Run this in each DB to see version
-- MySQL, PostgreSQL, SQLite
-- Shows how to connect and query

This simple query shows how to check the version of each database system.

Execution Table

Step	Database	Query	Result Example	Notes
1	MySQL	SELECT VERSION();	8.0.28	Returns MySQL version string
2	PostgreSQL	SELECT VERSION();	PostgreSQL 14.1	Returns PostgreSQL version string
3	SQLite	SELECT sqlite_version();	3.36.0	Returns SQLite version string
4	Decision	Compare features	MySQL: fast, popular PostgreSQL: advanced, standards SQLite: lightweight, embedded	Choose based on project needs
5	Exit	N/A	N/A	Decision made, no more queries

💡 After checking versions and features, choose the database that fits your project best.

Variable Tracker

Variable	Start	After MySQL	After PostgreSQL	After SQLite	Final
Selected_DB	None	MySQL	PostgreSQL	SQLite	Based on needs

Key Moments - 3 Insights

Why do MySQL and PostgreSQL use different version functions?

MySQL and PostgreSQL have different system functions; MySQL uses SELECT VERSION(), PostgreSQL also uses SELECT VERSION(), but SQLite uses SELECT sqlite_version(). This is shown in execution_table rows 1-3.

When should I choose SQLite over MySQL or PostgreSQL?

SQLite is best for small, embedded apps or testing because it is lightweight and serverless, as noted in the concept_flow and execution_table row 3.

Is PostgreSQL always better than MySQL?

Not always; PostgreSQL has advanced features and standards compliance, but MySQL is often faster and more popular for web apps. The choice depends on your project needs (execution_table row 4).

Visual Quiz - 3 Questions

Look at the execution_table, what version string does SQLite return at step 3?

A 3.36.0

B 8.0.28

C PostgreSQL 14.1

D Unknown

💡 Hint

Check the 'Result Example' column in execution_table row 3.

At which step does the decision about which database to use happen?

A Step 1

B Step 3

C Step 4

D Step 5

💡 Hint

Look at the 'Step' and 'Notes' columns in execution_table to find where the comparison is made.

If you want a lightweight embedded database, which variable value in variable_tracker should you pick?

A PostgreSQL

B SQLite

C MySQL

D None

💡 Hint

Refer to variable_tracker 'Selected_DB' and concept_flow descriptions about lightweight options.

Concept Snapshot

MySQL vs PostgreSQL vs SQLite:
- MySQL: popular, fast, good for web
- PostgreSQL: advanced features, strong SQL
- SQLite: lightweight, embedded, no server
Choose based on project size, features, and deployment needs.

Full Transcript

This visual execution compares three popular databases: MySQL, PostgreSQL, and SQLite. We start by checking their versions using simple queries. MySQL returns a version like 8.0.28, PostgreSQL returns a string like 'PostgreSQL 14.1', and SQLite uses a different function returning '3.36.0'. Then, we compare their main features: MySQL is fast and popular for web apps, PostgreSQL offers advanced features and strong SQL compliance, and SQLite is lightweight and embedded, ideal for small apps. The variable tracker shows how the selected database changes as we consider each option. Key moments clarify common confusions about version functions, when to choose SQLite, and that PostgreSQL is not always better than MySQL. The quiz tests understanding of version outputs, decision steps, and database choice for lightweight needs. This helps beginners see the differences clearly and decide which database fits their project best.

Practice

1. Which database is best known for being lightweight and easy to set up without a server?

easy

A. SQLite

B. MySQL

C. PostgreSQL

D. Oracle

Solution

1. Step 1: Understand SQLite's design

   SQLite is designed as a serverless, self-contained database engine, making it lightweight and easy to use.

2. Step 2: Compare with other databases

   MySQL and PostgreSQL require server setup, unlike SQLite.

3. Final Answer:

   SQLite -> Option A

4. Quick Check:

   Lightweight and serverless = SQLite [OK]

Hint: Lightweight and no server means SQLite [OK]

Common Mistakes:

• Confusing MySQL as lightweight
• Thinking PostgreSQL is serverless
• Choosing Oracle which is not open-source

2. Which of the following is the correct way to start a MySQL server from the command line?

easy

A. service mysql start

B. mysql --start

C. start mysql

D. mysql start-server

Solution

1. Step 1: Recall MySQL server start commands

   On many systems, MySQL server is started using system service commands like 'service mysql start'.

2. Step 2: Check other options

   'mysql --start', 'start mysql', and 'mysql start-server' are not valid MySQL server start commands.

3. Final Answer:

   service mysql start -> Option A

4. Quick Check:

   Use system service command to start MySQL [OK]

Hint: Use 'service mysql start' to launch MySQL server [OK]

Common Mistakes:

• Using 'mysql --start' which is invalid
• Trying 'start mysql' which is not a command
• Confusing client commands with server commands

3. Given the following SQL snippet run on PostgreSQL, what will be the output?

SELECT version();

medium

A. An error because version() is not supported

B. Empty result set

C. The MySQL version string

D. The PostgreSQL version string

Solution

1. Step 1: Understand the version() function in PostgreSQL

   PostgreSQL supports the version() function which returns the current version string of the server.

2. Step 2: Evaluate the query output

   The query returns a single row with the PostgreSQL version details.

3. Final Answer:

   The PostgreSQL version string -> Option D

4. Quick Check:

   version() returns PostgreSQL version info [OK]

Hint: version() shows PostgreSQL version info [OK]

Common Mistakes:

• Assuming version() is MySQL-only
• Expecting an error from version()
• Thinking it returns empty result

4. You try to run this SQLite command but get an error:

CREATE DATABASE testdb;

What is the problem?

medium

A. Database name 'testdb' is reserved

B. Syntax error in the command

C. SQLite does not support CREATE DATABASE command

D. You need to specify a file path

Solution

1. Step 1: Understand SQLite database creation

   SQLite does not use CREATE DATABASE; it creates databases by opening a file.

2. Step 2: Analyze the error cause

   Using CREATE DATABASE causes an error because SQLite expects a file to open, not a database creation command.

3. Final Answer:

   SQLite does not support CREATE DATABASE command -> Option C

4. Quick Check:

   SQLite creates DB by file, no CREATE DATABASE [OK]

Hint: SQLite creates DB by file, no CREATE DATABASE command [OK]

Common Mistakes:

• Assuming CREATE DATABASE works in SQLite
• Thinking syntax is wrong
• Believing database names are reserved words

5. You want to choose a database for a web app that needs complex queries, full ACID compliance, and extensibility. Which is the best choice?

hard

A. SQLite

B. PostgreSQL

C. MySQL

D. MariaDB

Solution

1. Step 1: Identify requirements

   The app needs complex queries, full ACID compliance, and extensibility.

2. Step 2: Match database features

   PostgreSQL is known for advanced features, strong ACID compliance, and extensibility compared to SQLite and MySQL.

3. Final Answer:

   PostgreSQL -> Option B

4. Quick Check:

   Advanced features and ACID = PostgreSQL [OK]

Hint: Advanced features and ACID compliance point to PostgreSQL [OK]

Common Mistakes:

• Choosing SQLite for complex queries
• Picking MySQL over PostgreSQL for extensibility
• Confusing MariaDB as more advanced than PostgreSQL