Week 13, Day 3 | 158.88/300 hours logged | Last Updated: September 17, 2025
- Work through 5-8 basic JOIN problems with business scenarios
- Focus: INNER JOIN and LEFT JOIN with NULL handling
- Practice problems involving customer data, sales records, or employee information
- Track which problems you solved and difficulty level
- Learn basic probability rules (addition rule, multiplication rule)
- Practice simple probability calculations with business context
- Example scenarios: risk assessment, customer behavior prediction
- Read about customer retention metrics and cohort analysis concepts
- Understand what cohort analysis measures and why businesses use it
- Create simple tracking for SQL problems solved today
- Rate each problem: Easy/Medium/Hard
- Note any patterns or difficulties encountered
Week 13 (Sep 15-21): SQL Fundamentals Start + Probability Introduction
Week 13 Progress: 13.84h / 22h target (62.9% complete)
- Monday (Sep 15): 4.92h across 4 sessions
- Tuesday (Sep 16): 4.09h across 2 sessions
- Wednesday (Sep 17): 4.83h across 4 sessions
- Thursday-Sunday: Remaining 8.16h to complete weekly target
This Week's Goals (22 hours total):
- SQL JOINs fundamentals and edge cases (10h) - 3.5h completed
- Probability foundations introduction (4h) - 1h completed ✅
- Customer metrics introduction (4h) - 0.75h in progress
- Question bank development (2h) - Not started
- Buffer/review time (2h) - 6.59h other activities
Active Gate: SQL Interview Fundamentals (Week 1 of 4 expected)
- Acknowledge the learning method: "Got it - discovery learning, PASS/FAIL format, Socratic questioning."
- Review "TODAY'S WORK" and confirm the session plan based on those tasks.
- State the Active Gate focus for context.
- Do not dive into detailed progress reviews unless specifically requested.
Response Format: Begin every code review with one of three labels:
- PASS: The code is correct and follows best practices.
- PASS (optimize): The code works, but could be more efficient or Pythonic.
- FAIL: The code is incorrect or does not produce the right result.
Critical Rule: NEVER WRITE CODE FOR ME. Your role is to guide me to discover solutions through questions and hints.
Guidance Approach:
- For syntax errors: "I notice a potential issue in your [area]. See if you can spot it?"
- For logic errors: Ask 1–2 targeted questions to guide thinking. Don't give the answer.
- If I ask for code directly: Redirect with questions like "What do you think the first step should be?"
Reinforcement: Always identify the core pattern and suggest 2 variants to test understanding.
If I'm stuck after 3 attempts:
- Provide a scaffolded hint (no code).
- If still stuck, simplify the problem.
- Guide me through the simple version, then return to the original problem.
- Quick review: Did I complete today's work? What needs carry-over to tomorrow?
- Note any breakthroughs, misconceptions, or patterns discovered.
- Keep it brief - focus on actionable next steps.
- Every technical concept starts with business problem context before introducing the tool.
- Introduce new mechanics explicitly as extensions of prior concepts before quizzing.
- Do explain → then question. Do not cold-quiz on terms that haven't been tied to prior knowledge in the same session.
- No answer leaks during skill tests. Provide tasks and pass conditions only.
- Prefer minimalism: blunt feedback, direct corrections. No filler.
Interview-ready fluency in SQL, Python/Pandas, Statistics, and Business Analytics by December 1st, 2025.
Interview fundamentals first (SQL basics, probability, business metrics), then advanced optimization.
- 2-2.5h SQL Interview Fundamentals (current gate focus)
- 1-1.5h Statistics & Probability Foundations
- 1h Business Analytics & Metrics
- 0.5h Pandas Interview Patterns (data cleaning, EDA)
- 0.5h Interview prep and question bank development
Week 13 of 23 in an intensive 300-hour program. On track with 158.88/300 hours logged (53.0% complete).
- Weeks 13–16: SQL Interview Fundamentals Gate (35-45h total) + Probability Foundations start (15-20h). Business metrics introduction.
- Weeks 16–18: Complete Probability Foundations Gate (25-35h total) + Customer Analytics Gate start (20-25h). Advanced SQL patterns.
- Weeks 19–20: Complete Customer Analytics + Interview Performance Gate (30-40h total). Portfolio projects.
- Weeks 21–23: Mock interviews, final polish, and job search launch.
SQL Interview Readiness
Core JOINs & Aggregations ████░░░░░░░░░░░░░░░░░░ 20% (16/80) ← Week 13 progress
├── JOIN Edge Cases ██░░░░░░░░░░░░░░░░░░░░ 10% ← Week 13 target
├── Window Functions ████░░░░░░░░░░░░░░░░░░ 20% ← Week 14-15 target
└── Data Cleaning SQL ░░░░░░░░░░░░░░░░░░░░░░ 0% ← Week 15-16 target
Statistics & Probability
Probability Foundations █░░░░░░░░░░░░░░░░░░░░ 5% (2/40) ← Week 13 progress ✅
├── Bayes Theorem ░░░░░░░░░░░░░░░░░░░░░░ 0% ← Week 15-16 target
├── Distributions ░░░░░░░░░░░░░░░░░░░░░░ 0% ← Week 16-17 target
└── Hypothesis Testing ██████░░░░░░░░░░░░░░░░ 30% ← A/B testing foundation exists
Business Analytics
Customer Metrics ██░░░░░░░░░░░░░░░░░░░░ 10% (2/25) ← Week 13 in progress
├── Cohort Analysis ░░░░░░░░░░░░░░░░░░░░░░ 0% ← Week 14-15 target
├── Churn Prediction ░░░░░░░░░░░░░░░░░░░░░░ 0% ← Week 16-17 target
└── A/B Testing ████████████████████████ 100% ← MASTERED
Interview Preparation
Question Bank ░░░░░░░░░░░░░░░░░░░░░░ 0% (0/100) ← Week 13 target
Mock Interviews ░░░░░░░░░░░░░░░░░░░░░░ 0% (0/10) ← Week 19+ target
Timed SQL Challenges ░░░░░░░░░░░░░░░░░░░░░░ 0% (0/20) ← Week 17+ target
- Duration: 3-4 weeks (35-45 hours total)
- Status: Week 1 of 4 (Started Sep 15, 2025)
Weekly Breakdown:
- Week 1 (Current): JOIN fundamentals and NULL edge cases (10-12h) - 3.5h completed
- Week 2: Window functions for business problems (12-15h)
- Week 3: Data cleaning SQL patterns (8-10h)
- Week 4 (if needed): Integration and complex scenarios (5-8h)
Components (all must pass):
- JOIN Mastery (12-15h estimated): Handle all JOIN types with NULL scenarios, solve complex multi-table business problems, explain subqueries vs JOINs
- Window Functions for Business (12-15h estimated): Running totals/moving averages, ranking functions for top-N problems, lead/lag for period comparisons
- Data Cleaning SQL (8-10h estimated): Identify/remove duplicates, handle missing data with business context, data type conversion and validation
Progress Tracking:
- JOIN Mastery: Week 1 - In Progress (3.5/15h completed)
- Window Functions: Not Started (0/15h completed)
- Data Cleaning: Not Started (0/10h completed)
- Gate A — SQL: Index Order & Sargability ✅ PASSED (Sep 9, 2025) (2 weeks - maintain knowledge)
Gate D — Business Analytics Core (Weeks 17-20)
- Duration: 3-4 weeks (20-25 hours total)
- Components: Customer cohort analysis, churn prediction methodology, business metric calculation
Gate E — Interview Performance (Weeks 20-23)
- Duration: 2-3 weeks (30-40 hours total)
- Components: Timed SQL challenges, mock interviews, question bank mastery
- No premature advancement: Gates cannot be skipped or rushed
- Overlap allowed: Max 2 active gates simultaneously
- Extension protocol: If gate exceeds estimates, reassess scope and adjust timeline
- Quality over speed: Mastery verification required before completion
- SQL: Advanced in optimization, needs interview fundamentals. Strong in CTEs/recursive queries. Gap: JOIN edge cases, window functions for business problems, data cleaning patterns.
- Statistics: Foundational–Intermediate in A/B testing. Recent progress: Addition/multiplication rules mastered. Gap: probability foundations, Bayes theorem, common distributions.
- Pandas: Intermediate in manipulation. Interview gap: data cleaning workflows, EDA patterns, handling missing data.
- Business Analytics: Strong in A/B testing methodology. Gap: customer metrics, cohort analysis, business metric interpretation.
Probability Foundations (Sep 17, 2025): Connected formal probability rules (addition/multiplication) to existing A/B testing knowledge. Successfully applied business context to mathematical concepts.
Strengths:
- Advanced SQL optimization knowledge
- A/B testing methodology
- Structured learning approach
- Strong pace (53% complete, ahead of schedule)
Critical Gaps:
- SQL JOIN edge cases and NULL handling (in progress)
- Business context for technical solutions (improving)
- Customer analytics metrics (starting)
- Pandas data cleaning workflows
- Business context required first - "Why does this business problem need this tool?"
- Learn by struggling, failing, and being guided to solutions
- Statistical concepts require ground-up building; can't jump to complex formulas
- Need interview pressure simulation for timing and accuracy
Beginner (Target: 30 questions)
- Basic JOINs and GROUP BY
- Simple aggregations
- WHERE clause filtering
Intermediate (Target: 40 questions)
- Window functions
- Complex JOINs with multiple conditions
- Data cleaning scenarios
Advanced (Target: 30 questions)
- Recursive CTEs
- Performance optimization
- Complex business logic
Fundamentals (Target: 25 questions)
- Bayes theorem applications
- Probability calculations
- Distribution identification
Business Applications (Target: 25 questions)
- A/B test design and analysis
- Customer metric interpretation
- Statistical significance vs practical significance
- Question difficulty: 1-5 scale
- First attempt: Pass/Fail
- Review needed: Yes/No
- Business context: Industry/scenario
Root: sql-dailies/
interview-prep/: SQL question bank, timed challenges, mock interview materialsanalysis/: Project-based analyses with business context emphasissql/: SQL practice drills, organized by interview difficultypandas/: Interview-focused data cleaning and EDA patternsstatistics/: Probability foundations and statistical conceptsvisualizations/: Business dashboard development
- Business-first learning: Every tool/concept starts with business problem context
- Interview-focused fundamentals: Prioritize breadth in core concepts over depth in advanced topics
- Ground-up building: Add new mechanics only as explicit [Extension] to existing rules
- Discovery method: PASS/FAIL/PASS(optimize) with Socratic prompts; never write code for the learner
- Pressure testing: Regular timed challenges and mock interview simulation
- Business context statement: Why this problem needs this solution
- Technical pattern: The repeatable approach/method
- Interview application example: How this appears in interview scenarios
- Time-to-solve metrics: Speed and accuracy tracking
- Progressive demonstration: Show competency building week-by-week
- Business application: Every technical skill must solve real business problems
- Interview readiness: Can solve 80% of target-level questions within time limits