Tag: sql

All the articles with the tag "sql".

• Data Engineering Study #1 — Coffee and coffee Are Different Values

  23 Aug, 2026

  I started studying data engineering. Two days of notes on deliberately creating a dirty CSV to see how case sensitivity and empty values break aggregations, plus the principle of never touching raw data and cleaning it in staging instead, and learning UPPER, CASE, and COALESCE.

• PostgreSQL Basics — CRUD and the Korean Sorting (COLLATE) Trap

  14 Jul, 2026

  I'd only used SQLite before, so this was my first time touching PostgreSQL. From CREATE to mapping CRUD, and the collation problem where ORDER BY wouldn't sort Korean text alphabetically.