Database Plain-English Query Skill

The database plain-English query skill is a free Claude skill for asking your own database questions in normal language, such as “how many customers signed up last month” or “top 10 products by revenue”. Claude reads the real schema, writes one SELECT, runs it through the Database add-on of MCP Self-hosted and shows you the SQL next to the answer.

What does the database plain-English query skill return?

Four parts, every time:

• The answer in one sentence.
• A small result table.
• The exact SQL it ran, so you can rerun or adjust it yourself.
• The assumptions it made, for example which column it treated as the signup date or which status values it counted as paid.

The assumptions are the useful part. “Revenue” can mean order totals, line totals or totals minus refunds. The skill states which one it used, so you can correct it in one sentence instead of finding out later that the number was off.

How does the database plain-English query skill avoid guessing?

It looks before it queries. First it lists the tables and describes the ones that look relevant: column names, data types, nullability and defaults. Then it runs a few small probe queries to see real values, such as the status codes in an orders table, the date format or whether amounts are stored in cents. Only then does it write the query that answers your question, with an explicit date range and a row limit.

This takes a few more calls than writing SQL straight away. It also prevents the classic mistakes: a column name that does not exist, a status filter on “paid” when the table says “completed”, or a sum in cents reported as euros.

Which tools does the database plain-English query skill use?

The three tools of the Database MCP add-on:

• database_list_tables lists the base tables. Views are not in that list, though a SELECT on a view you name works.
• database_describe_table returns column name, type, nullability and default. It does not show indexes or foreign keys, so Claude infers joins from column names and probe queries.
• database_query runs one SQL statement per call. Results stop at 200 rows by default, and a query is cut off after 10 seconds by default.

Both limits are yours to change with DB_MAX_ROWS and DB_QUERY_TIMEOUT_MS. For aggregate questions, the 200-row cap rarely matters: the skill groups and sums in SQL, not in the chat.

Can the database plain-English query skill change data?

No. It only writes SELECT statements, even when the seat has Can make changes on. The add-on adds its own guard: on a read-only seat any statement containing INSERT, UPDATE or DELETE is refused, and CREATE, DROP, ALTER, TRUNCATE, GRANT and REVOKE are refused in every mode. That check works on keywords, so a SELECT that mentions the word “delete” in a text filter is refused on a read-only seat too. Rephrase the filter if that happens.

The real protection sits in your database, not in Claude. Connect the add-on with a database user that only has SELECT rights, ideally only on the tables that should be queryable. The Database MCP setup guide explains how.

What do you need to run the database plain-English query skill?

MCP Self-hosted and the Database add-on. MCP Self-hosted costs € 217,80 excl. VAT: € 180,00/yr including 3 seats, and the Database add-on is € 108,90 excl. VAT: € 90,00 per year. The download is free and needs no license.

The add-on works with MySQL, MariaDB and other MySQL-compatible databases, and with PostgreSQL. The connection details go in .env:

DB_TYPE=mysql
DB_HOST=db.example.com
DB_NAME=shop
DB_USER=claude_readonly
DB_PASSWORD=...

DB_PORT and DB_SSL are optional. For PostgreSQL, set DB_TYPE=postgres.

How do you install the database plain-English query skill?

1. Download it from this page. Checkout is free, and the zip appears under Skills in My Account.
2. Claude Code: unzip into ~/.claude/skills/, or into .claude/skills/ for a single project.
3. Claude Desktop: add the zip through Claude’s skills settings.
4. Ask a question you already know the answer to, and compare.

Prompts that work: “How many orders did we get per week this quarter?”, “Which customers spent more than 1,000 last year?” or “What is the average order value by country?”

Who is the database plain-English query skill for?

People who need numbers from a database but do not write SQL daily: account managers, shop owners, support leads. Developers use it too, as a fast first draft of a query on an unfamiliar schema, with the SQL right there to review.

The database plain-English query skill is free. Download it here, see the other skills in the Claude skills catalog, or read the free Claude skills overview to see how skills and add-ons fit together.