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Pentesting

Planning Your First Web Application Pentest: Scope, Safety, and Evidence

Build a focused web pentest plan with clear authorization, realistic objectives, controlled testing, and evidence that developers can use.

D Putu Adi Guna Permana · 3 min read
FOR YOUR CURIOSITY

Latest notes.

LEARNING SQL / NOTES</>↗
Learning SQL13 Aug 2026

How do I use SQL string, number, and date functions?

SQL databases store raw values, but real reports rarely display them exactly as stored. Names may need to be capitalized, prices rounded, and dates formatted in a friendlier way. SQL provides built-in functions that transform values directly inside a query, so the database returns exactly what your application or report needs. In this tutorial, you […]

Wayan · 9 min read
LEARNING SQL / NOTES</>↗
Learning SQL12 Aug 2026

How do I perform calculations in a SELECT statement?

A SELECT statement is not limited to returning columns exactly as they are stored. You can compute new values on the fly — the total price of an order line, a discount, a tax amount, the age of a record, or the concatenation of a first and last name. These calculations happen inside the database […]

Wayan · 12 min read
LEARNING SQL / NOTES</>↗
Learning SQL11 Aug 2026

How do I rename columns and tables using SQL aliases?

When you write SQL queries, the column names in your result often come straight from the table definition. Names such as unit_price or order_date are useful in the database, but they may look technical in a report, or they may collide when you join two tables that both contain a column called id. SQL solves […]

Wayan · 7 min read
LEARNING SQL / NOTES</>↗
Learning SQL10 Aug 2026

How do I filter values using IN, BETWEEN, and NOT in SQL?

When you filter rows in SQL, you often need to match a value against a list of options, check whether it falls within a range, or exclude rows that satisfy a condition. Chaining many AND/OR comparisons for these cases quickly becomes hard to read. SQL provides three operators — IN, BETWEEN, and NOT — that […]

Wayan · 12 min read
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Putu Adi Guna Permana
ABOUT THE AUTHOR

Dr (C). Ir. Putu Adi Guna Permana, S.Kom., M.Kom., IPM., ASEAN Eng.

Writer and founder of Diary Coding — sharing notes, tutorials, and experiences about programming for anyone who wants to keep learning.