YAML
Keeping Secrets Out of YAML Config Files and Git History
A password removed from a YAML file stayed in Git history. Reference secrets by name, scan the tree and the history, and rotate anything that was committed.
6 min read
Library
Everything you need to level up your coding skills.
Excel
Writing the Same Excel Pivot Table as a GROUP BY Query
Map each part of an Excel pivot table to SQL: rows to GROUP BY, values to aggregates, columns to CASE, filters to WHERE and totals to ROLLUP.
6 min read
CSV
Loading Many CSV Files Into One SQLite Database in Bash
A bash loop that imports monthly CSV files into one SQLite table, records which file each row came from, and refuses to load a file twice.
7 min read
JSONGuide
Using the JSON Column Type in MySQL Without Regret
A working guide to MySQL 8.4 JSON columns: paths, reading, updating, searching, generated-column and multi-valued indexes, and MariaDB differences.
19 min read
XML
Summarizing a Large XML Export With a Streaming Parser
Total amounts by currency and top SKUs over 20,000 invoices in one streaming pass with Decimal, 21 MB of memory, and the same USD total as a tree-based check.
6 min read
Excel
Grouping Dates by Month or Quarter in a Pivot Table
Group dates in a pivot table by month, quarter or year, fix the Cannot group that selection error, handle fiscal quarters, and do the same grouping in SQL.
6 min read
CSV
Fixing Expected Columns but Found Errors in SQLite Imports
SQLite prints expected N columns but found M and loads the row anyway, with exit status zero. See each import message and what it did to the data.
7 min read
Excel
Making a Pivot Table From Data Larger Than Excel Allows
A sheet holds 1,048,576 rows, but a pivot can read more. Use the Data Model, pre-aggregate in SQL or DuckDB, or sample, and know where each approach stops.
6 min read
CSV
Exporting a SQLite Query Result to CSV From the Shell
Export a SQLite query to CSV with the shell, see exactly how 3.54 quotes values, writes NULL and ends lines, and learn which options change each.
8 min read
XML
Counting Elements and Attributes in an Unknown XML File
Profile an XML file you have never seen in 0.2 seconds and 21 MB of memory, by counting every element and attribute path with iterparse, and read the profile.
7 min read
YAML
Splitting a Large YAML Config Into Several Files Cleanly
YAML has no include. Two ways to split a config: numbered fragments merged in order, and a custom include tag on a safe loader. Both tested, with traps.
7 min read
JSON
When JSONB Is the Wrong Choice and Typed Columns Win
Signs that a PostgreSQL JSONB column should be real columns, what the workarounds cost, and a step-by-step migration that keeps the data and adds constraints.
8 min read
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