YAML
Using Anchors to Reduce Repetition in YAML Config Files
Put shared settings in one anchored block and merge it into each service. The web service replaced the whole environment block, since the merge is shallow.
6 min read
Tag
how-to
590 posts
JSON
Updating Parts of a MySQL JSON Document in Place Safely
Use JSON_SET, JSON_REPLACE, JSON_REMOVE and array functions to change one part of a MySQL JSON column, with partial updates, binlog size and the counter trap.
8 min read
Excel
Calculating Percent of Total in a Pivot and in SQL
Show values as percent of total in an Excel pivot, then write the same share in SQL with SUM OVER and avoid integer division and rounding traps.
6 min read
CSV
Letting DuckDB Sniff the Delimiter and Types of a CSV
How the DuckDB CSV sniffer picks delimiter, header and types, how to read its verdict with sniff_csv, and what breaks when a bad value sits past the sample.
9 min read
CSV
DuckDB read_csv Options You Will Actually Need in Practice
The read_csv options that solve real problems in DuckDB 2.0, each on a file that needs it, including the nullstr trap that replaces the empty default.
7 min read
Excel
Unpivoting Columns Back Into Rows in SQL for Excel Data
Turn a wide Excel sheet with a column per month into a long table: LATERAL VALUES in PostgreSQL, UNPIVOT or CROSS APPLY in SQL Server, UNION ALL in MySQL.
6 min read
JSON
JSON_EXTRACT and the Arrow Operators in MySQL Explained
How MySQL JSON paths work, what JSON_EXTRACT returns for each value type, why -> and ->> are not the same, and the path rules that cause errors.
7 min read
CSV
How to Run SQL Directly on a CSV File With the DuckDB CLI
Install DuckDB, point it at a CSV and query it. Covers the file name shortcut, DESCRIBE, SUMMARIZE, reading from a pipe and writing CSV back out.
7 min read
YAML
Environment Specific YAML Config Without Copy and Paste
Keep one base file and small overrides per environment, merge them in order and print the effective config with the source of each value. Tested layers.
6 min read
Excel
Pivoting Rows Into Columns in MySQL and SQL Server
Pivot in MySQL with SUM and CASE, and in SQL Server with the PIVOT operator. Includes dynamic column lists built with prepared statements and QUOTENAME.
7 min read
XML
Analyzing Podcast and Blog Feeds From XML With Python
Turn an RSS podcast feed into cadence, duration and size numbers, handle itunes durations in two formats and RFC 822 dates, and compare with feedparser.
6 min read
Editor's pick
CSVGuide
Querying CSV Files With DuckDB Instead of Loading Them
DuckDB runs SQL on a CSV file with no import, no schema and no server. See what it guesses, what that costs, where it fails, and how to make it strict.
22 min read