Stop 04 · Data & Metrics for PMsTopics · 8/12

SQL Basics for PMs

In short

Waiting two days for an analyst to answer "how many orders came from Pune?" slows everyone down. A little SQL lets you answer your own questions in minutes.

Enough SQL to pull your own data without waiting on an analyst — SELECT, WHERE, GROUP BY, JOIN and basic aggregate functions cover the vast majority of a PM's real needs.

The purple blob stands at a library counter beside tall wooden catalogue drawers.

Think of it like this

Asking the librarian

You tell the librarian: "Give me books by this author, only from after 2020, newest first, just the top five." She checks the catalogue and hands them over. SQL is that same request, written so a database understands.

Watch it happen

One question, one query

Database

FROM orders

1/6Start by choosing the table. Here, every order ever placed, one row per order.

The big ideas

What you need to know

Tables are spreadsheets

Rows are records, like one order each. Columns are fields, like city and amount.

WHERE filters rows

Keep only the rows you care about before counting anything.

GROUP BY summarises

Combine rows into groups, then use COUNT, SUM or AVG on each group.

JOIN connects tables

Orders store a user_id. A JOIN pulls in that user's details from the users table.

See it in code

Walk through the code

sql

1SELECT city,2       COUNT(*) AS orders,3       ROUND(AVG(amount), 0) AS avg_order4FROM orders5WHERE created_at >= '2026-01-01'6GROUP BY city7ORDER BY orders DESC8LIMIT 5;

1/4Pick the columns to show: city, an order count and the average amount.

Top five cities by orders this year, with the average order value. This runs in PostgreSQL, MySQL and most SQL tools.

Save yourself the pain

Common mistakes

Oops

Running SELECT * on a huge table with no LIMIT.

Do this instead

Add LIMIT while exploring, and select only the columns you need.

Oops

Trusting a number without checking how the query counts.

Do this instead

Spot-check a few rows and ask an analyst to review queries used in big decisions.

Your mission

Answer three questions in SQL

~40 min

Quick check

You want the number of orders per city. Which clause do you need?

Go deeper

1Complete a beginner SQL course or interactive tutorial (many are free).
2Practice writing a query to count daily signups from a sample dataset.
3Learn just enough JOIN logic to combine a users table with an events table.