The ledger said €8.3 million was overdue. By the dates, it was €4.0 million.
Someone hands you a company's books and a question: is the company in good shape? The answer is not in any one row. It is spread across a budget, a ledger of invoices and a record of cash, and some of what the tables say is wrong. Getting from the files to an answer someone can act on is most of what an analyst does.
Follow the Money teaches that work from the beginning. It assumes no SQL. It teaches the language by asking one company's books the questions a finance team asks, then shows how to find what is wrong in the data, fix it in a way that can be explained, and turn the result into a message: a report, a dashboard or a single number, with a chart that answers the question honestly.
It is written in SQL on DuckDB, and every move is shown again in a spreadsheet and in pandas, with the differences that matter in PostgreSQL, SQL Server and MySQL.
Inside:
- What a company's books record, why profit is not cash, and how to read a table you have been handed
- The working core of SQL, learned on finance questions: which lines, how much in total, how much by department, what is overdue and how late, what joins to what, and questions built from other questions
- Budget-versus-actual reports, favorable and unfavorable variance, materiality, aging reports and the three activities of a cash flow statement
- Finding what is wrong: a reversal booked as spending, a status column wrong in both directions, dates that should not exist, totals that do not tie; then saving the fixes as views so nobody has to remember them
- A finance scorecard built query by query and checked a second way in pandas
- From numbers to a message: the reader and the decision, finding the story, report vs dashboard vs single number, the chart that follows the question, and ten ways a true chart can mislead
The examples use four tables from Clearstone, a fictional company: its budget, its invoices, its cash movements and its departments. The chapters run 251 queries against them, each printed with its actual result, and 73 figures show what the queries do and how the findings can be drawn.
The quickest way to run the examples is the LucidPlexus Workbench, a SQL notebook in your browser with the tables already loaded: nothing to install, and the data never leaves your machine. They also run unchanged in any copy of DuckDB. Data: lucidplexus.com/community/dataset.php?slug=clearstone-financial-operations
For people in or near finance and operations who have been handed data and a question, first-year analysts, and students. No SQL needed to start.
Every purchase includes the companion download: the two-page cheat sheet, the workbook, the SQL file for every chapter with a script that checks each result against the book, and the four data tables.
A LucidPlexus Field Book. First edition, 2026.