Hey Reader, Imagine you're presenting a finding to your team: "Customer A spent $4,200 with us." The first question from the room: "Is that a lot?" Most analysts learning SQL don't realize that, without context, the number means nothing. You need comparison. Is the average customer spend $500 or $5,000? Is $4,200 in the top 10% or the middle of the pack? This is the "compared to what?" problem, and subqueries solve it elegantly. Numbers without context don't drive decisions. Executives don't...
11 days ago • 4 min read
Hello Reader, Almost every business question boils down to one of two things: "How many?" (COUNT) "How much?" (SUM) How many customers booked this month? How much revenue did we generate? How many trips were cancelled? How much did we lose? Once you're comfortable with COUNT and SUM, you can answer the majority of questions that come your way (like sales analytics using SQL). Let me show you both patterns using a real business scenario. The Scenario Your operations manager asks: "Give me a...
18 days ago • 4 min read
HeyReader, Most analysts never think to ask: "Why are our customers cancelling?" Everyone looks at bookings. Everyone reports revenue. But the data hiding in your cancelled orders often tells a more important story than your completed ones. And analysts that want to move from beginner to intermediate SQL skill level have an unfair advantage here. Because there's a sequence to work through this kind of problem. That's what we're covering here. At Summit Adventures (the fake adventure tourism...
25 days ago • 4 min read
Hey Reader, Imagine you're a marketing analyst and your marketing director walks over and says: "I need our customers broken into spending tiers (VIP, Standard, and Low Value) so I can send different emails to each group." You have the data. But every customer just has a dollar amount. There's no "tier" column in the database. How do you create categories that don't exist yet? This is where CASE WHEN becomes one of the most useful tools in your SQL toolkit. The problem is that raw data...
about 1 month ago • 4 min read
Hey Reader, This week's newsletter is different. Not a regular "how to solve problem X with SQL" kinda thing. Because I've realized something: you can write perfect queries and still never get the career impact you want. You need "soft skills" like presenting your results to leadership in addition to "technical skills" like using CTEs and WINDOW functions. Let me show you what I mean. The Scenario Wednesday, 2pm. Q2 review meeting. CMO: "Our booking conversion is down. What's causing it?"...
about 1 month ago • 4 min read
Hello Reader, Imagine this scenario: Your CMO walks into Monday's meeting with a question: "I need to see our top 3 highest-revenue expeditions in EACH category - hiking, climbing, safari, cultural, and photography." Most analysts would write 5 separate queries, one per category. Or export to Excel and manually filter. An hour of work, minimum. Confident analysts write one query using window functions. Takes 3 minutes. Here's the skill that separates intermediate analysts from advanced ones....
about 2 months ago • 6 min read
Hello Reader, One thing before we get into this week's tutorial on the magic of JOINs: I launched a new job board -- just for data people! 🥳 It's called DataJobsOnline.com (creative, I know). And I have been building out the data base of jobs over the past few weeks: 405 Remote Data Analyst Jobs 182 Mid-Level Jobs that require "SQL" 183 Tableau Jobs 38 Data Jobs in London You get the idea...it's a job board! For data professionals like you. If you're not job hunting right now, but know...
about 2 months ago • 5 min read
Hey Reader -- I'm trying something new this week! Can you take a minute to fill out this quick survey? Thanks in advance! Okay, on to this week's topic: Imagine you just got hired at as an analyst for a top-tier adventure tourism company (like Summit Adventures, the fake company I created to teach people like you how to solve real-world business problems with SQL) You start your first day on the job by opening your company database and seeing 1,600 rows of customer bookings. Varying prices....
2 months ago • 5 min read
Hey Reader -- I'm trying something new this week! Can you take a minute to fill out this quick survey? Thanks in advance! What are you interested in right now? Your answers will help shape the future of what I send each week! 🚀 More SQL Topics More Python Topics More Tableau Topics More Agentic AI Topics Okay, on to this weeks topic: Imagine this: Your boss walks into the Monday morning meeting and says "Show me revenue trends for the last 6 months." Everyone looks at you. Most analysts...
2 months ago • 3 min read