SQL – DBA Notes

performance SQL

𝗦𝗤𝗟 𝗤𝘂𝗲𝗿𝘆 𝗘𝘅𝗲𝗰𝘂𝘁𝗶𝗼𝗻 𝗢𝗿𝗱𝗲𝗿!

Bulent Soylu October 2, 2024

When you write an SQL query, the database engine executes the clauses in a specific order, which is different from the sequence in which you…

performance Postgres postgresql SQL

Postgres Execution Plans

In this blog post, we’ll see What is an SQL Execution Plan? Postgres documentation says: The execution plan shows how the table(s) referenced by the statement will…

MySQL Oracle Postgres SQL

How to Generate a Running(Accumulated) Total in SQL

Bulent Soylu October 1, 2023 accumulated sum cumulative sum over running sum

Have you ever needed to calculate a “running total” or “cumulative sum” in SQL? You can do this in SQL without any other programming language…

SQL

Advanced SQL Techniques You Should Know

Bulent Soylu May 28, 2023 data analysis SQL

Window Functions Window functions allow you to perform calculations across a set of rows that are related to the current row. For example; we have…

SQL

Correlated subquery

Bulent Soylu May 23, 2023 performance

In a SQL database query, a correlated subquery (also known as a synchronized subquery) is a subquery (a query nested inside another query) that uses values from the outer query. Because…

Oracle SQL

Finding Empty Tablespaces in Oracle

Bulent Soylu January 9, 2023 oracle performance tablespaces

I’m given a task to find the empty tablespaces.I’ve checked dev server and majority of the tables’ stats were locked.This solution takes time but works.…

Linux performance SQL

Understanding IOPS vs. throughput

Bulent Soylu January 9, 2023 linux oracle performance

Input/output operations per second (IOPS) and data throughput are two popular performance characteristics of any storage system. In the early days of computer technology, when…