---
title: "Jessica Aki (@MazinoCodes) | Hashnode"
description: "Learning databases, data engineering, and building in public. Read the latest articles by Jessica Aki on Hashnode."
url: "https://hashnode.com/@MazinoCodes"
---

@MazinoCodes

# Jessica Aki

@MazinoCodes · Joined January 2026

Learning databases, data engineering, and building in public

### [I Built a PostgreSQL User Analytics System — Here’s What I Learned About Real](https://mazinocodes.hashnode.dev/i-built-a-postgresql-user-analytics-system-heres-what-i-learned-about-real?utm_source=hashnode&utm_medium=feed)

Learn how to build a PostgreSQL-based User Analytics system from scratch. Hands-on SQL queries for demographics, registrations, email analysis, and age rang

4 min read · [mazinocodes.hashnode.dev](https://mazinocodes.hashnode.dev/i-built-a-postgresql-user-analytics-system-heres-what-i-learned-about-real?utm_source=hashnode&utm_medium=feed)

[Jan 9](https://hashnode.com/posts/i-built-a-postgresql-user-analytics-system-heres-what-i-learned-about-real/69618f395786b8f5d3f090e8)

### [Learning SQL Subqueries as a Beginner: What Made Sense and What Didn’t](https://mazinocodes.hashnode.dev/learning-sql-subqueries-as-a-beginner-what-made-sense-and-what-didnt?utm_source=hashnode&utm_medium=feed)

A beginner-friendly walkthrough of SQL subqueries using real SQLZoo exercises. Includes SELECT-in-SELECT examples, common patterns, and where correlated sub

4 min read · [mazinocodes.hashnode.dev](https://mazinocodes.hashnode.dev/learning-sql-subqueries-as-a-beginner-what-made-sense-and-what-didnt?utm_source=hashnode&utm_medium=feed)

[Jan 9](https://hashnode.com/posts/learning-sql-subqueries-as-a-beginner-what-made-sense-and-what-didnt/69604c9249d71ed702ca762c)

### [Day Three with SQL: Inserting Data, Querying Smarter, and Working with Real Datasets](https://mazinocodes.hashnode.dev/day-three-with-sql-inserting-data-querying-smarter-and-working-with-real-datasets?utm_source=hashnode&utm_medium=feed)

Day three was all about reinforcing the basics, not rushing forward, but getting comfortable with SQL by practicing it repeatedly on real data. I spent most of today working through SQLZoo exercises, inserting data into PostgreSQL, and querying a rea...

3 min read · [mazinocodes.hashnode.dev](https://mazinocodes.hashnode.dev/day-three-with-sql-inserting-data-querying-smarter-and-working-with-real-datasets?utm_source=hashnode&utm_medium=feed)

[Jan 7](https://hashnode.com/posts/day-three-with-sql-inserting-data-querying-smarter-and-working-with-real-datasets/695ee8a4a261fd2f48249fc9)

### [Learning SQL in Practice: LeetCode Challenges and Setting Up PostgreSQL](https://mazinocodes.hashnode.dev/learning-sql-in-practice-leetcode-challenges-and-setting-up-postgresql?utm_source=hashnode&utm_medium=feed)

A beginner-friendly look at practicing SQL with LeetCode and setting up PostgreSQL, including table creation, constraints, and psql commands.

3 min read · [mazinocodes.hashnode.dev](https://mazinocodes.hashnode.dev/learning-sql-in-practice-leetcode-challenges-and-setting-up-postgresql?utm_source=hashnode&utm_medium=feed)

[Jan 7](https://hashnode.com/posts/learning-sql-in-practice-leetcode-challenges-and-setting-up-postgresql/695e1e0c148e939674575ee3)

### [Databases 101: My First Real Step into SQL](https://mazinocodes.hashnode.dev/databases-101-my-first-real-step-into-sql?utm_source=hashnode&utm_medium=feed)

Learn database fundamentals and SQL basics from scratch. A beginner-friendly walkthrough of databases, DBMS, keys, and essential SQL queries.

3 min read · [mazinocodes.hashnode.dev](https://mazinocodes.hashnode.dev/databases-101-my-first-real-step-into-sql?utm_source=hashnode&utm_medium=feed)

[Jan 6](https://hashnode.com/posts/databases-101-my-first-real-step-into-sql/695c5c6de7ed366be1dfa331)