Question 1

Who is this collection for?

Accepted Answer

Candidates preparing for **data analyst, product analyst, business analyst, and analytics-engineering** interviews at top companies.

**Specifically:** Amazon, Meta, Google, Stripe, Airbnb, Netflix, Uber, DoorDash, LinkedIn, Microsoft, Apple, Salesforce — and *50+ other consumer-tech, fintech, and SaaS companies*.

This is the **complete SQL prep path**; expect **~30 hours of focused work over 4-6 weeks**.

Question 2

How is this different from LDS SQL 50?

Accepted Answer

**LDS SQL 50** is the *general-purpose* SQL roadmap — 50 problems across all major patterns, designed for both interview prep AND day-job skill building.

**LDS Data Analyst Interview Prep 75** is purpose-built for the *analyst-track interview specifically*: it adds 25 more problems and reorganizes into **7 interview-shaped stages** including dedicated rounds for behavioral SQL (*"write a query that answers..."*) and edge-case pitfalls.

- **4+ weeks** before an interview → do **this** collection
- **2 weeks** → do **SQL 50**

Question 3

What SQL patterns does it cover?

Accepted Answer

**Every pattern** that appears in real DA interviews per public reports (DataLemur, StrataScratch, Interview Query, IGotAnOffer, Glassdoor):

- **Basic filtering** (`WHERE`, `IN`, `BETWEEN`)
- **Multi-table joins** (INNER, LEFT, anti-join, multi-FK star)
- **Conditional aggregation** (`SUM(CASE WHEN...)`)
- **Window functions** (RANK, ROW_NUMBER, LAG, NTILE, running totals, moving averages, Top-N per group)
- **CTEs** (single, multi-step, reference value)
- **Subqueries** (`EXISTS`, `NOT IN`, scalar)
- **Date arithmetic** (`JULIANDAY`, aging buckets)
- **CASE WHEN classification** (multi-rule tiering)
- **Set operations** (`UNION`, `EXCEPT`)
- **Multi-CTE business scorecards** (3-6 CTEs combined into per-entity classification)

Question 4

Why 75 problems? Why 7 stages?

Accepted Answer

**75 is the inflection point** for SQL interview prep — *enough coverage* to handle any pattern an interviewer throws, *few enough* to actually finish in 4-6 weeks.

The **7 stages mirror what a real interview flow looks like**:

foundation (phone screen warmup) → joins → analytics → production patterns → scorecards (the staff-level shape) → behavioral framing → edge cases.

*Each stage builds on the prior.*

Question 5

Is this only premium / paid?

Accepted Answer

**No.** Stage 1 has **5 free problems** (no login required) to let you start immediately.

The other 70 problems require **Premium** because they run on production-grade 8-15 table schemas modeled after real companies (*Stripe, Airbnb, Netflix*, etc.) — schemas at that fidelity require subscription access.

**Premium also includes:**
- AI Mentor
- step-by-step SQL Visualizer
- PostgreSQL/SQLite dual-dialect support

Question 6

What datasets does it use?

Accepted Answer

**All 15 LDS premium domains** (and 1 free retail schema for Stage 1):

AdTech, Banking, Fintech Trading, Healthcare Claims, **Lodging** (Airbnb-style), Logistics, Marketplace Food, **Marketplace Mobility** (Uber-style), **Payments** (Stripe-style), Real Estate, **Retail** (Amazon-style), **SaaS B2B** (Salesforce-style), **Social Graph** (Meta-style), **Streaming Media** (Netflix-style), Telecom & ISP.

*Max 6 problems per dataset — keeps the practice broad across industries.*

Question 7

How long does this take?

Accepted Answer

**Estimated ~30 hours of focused practice**, typically **4-6 weeks** at 2-3 problems per day.

- **Stage 5 (Business Scorecards) and Stage 6 (Behavioral)** are the densest — budget **25-35 minutes per problem**
- **Stages 1-2** can be done at *10-15 min per problem*

Question 8

Which SQL dialect does it use?

Accepted Answer

**SQLite by default** — runs in your browser via sql.js. **PostgreSQL mode** is also available via PGlite (also runs in browser).

All patterns taught transfer directly to **BigQuery, Snowflake, Redshift, MySQL, and SQL Server**.

*Date functions are sometimes the only thing that differs across dialects, and we use the most portable form throughout.*

Question 9

I have an interview next week. Can I still benefit?

Accepted Answer

**Yes.**

If you have less than 2 weeks, **work backwards**: start with **Stage 5 (Business Scorecards)** and **Stage 6 (Behavioral)** since those mirror the highest-difficulty rounds.

Skim Stages 1-4 only on patterns you feel weak on.

*For absolute crunch time, see our **LDS SQL 7-Day Sprint 25** collection (coming soon) — a 25-problem subset designed for one-week prep.*

Question 10

Will this work for Data Scientist or Data Engineer interviews too?

Accepted Answer

**Partially.**

- **Data Scientist interviews** add probability/statistics, A/B testing, and ML evaluation that this collection doesn't emphasize — see **LDS Data Scientist Interview Prep 75**, which covers all four DS interview surfaces (SQL + pandas + stats + ML) in a 6-round simulator
- **Data Engineer interviews** add system-design and schema-modeling rounds that aren't in this collection

*For the SQL portion of those interviews specifically, ~80% of this collection still applies.*

Question 11

How does this compare to DataLemur, StrataScratch, or LeetCode for Data Analyst interview prep?

Accepted Answer

All three are catalogs of SQL problems. Useful for last-mile drilling — but not built around the *shape* of a real DA onsite.

**What LDS DA Interview Prep 75 gives you that they don't:**

- **A 7-round onsite simulator**, not a flat problem list — phone screen → joins → analytics → production patterns → business scorecards → behavioral SQL → edge-case pitfalls
- **All 15 industry schemas** (Stripe-style payments, Airbnb-style lodging, Netflix-style streaming, Meta-style social graph) — the kind of schemas real DAs work on
- **Both SQLite and PostgreSQL** on every problem — toggle dialects freely
- **SQL Visualizer + AI Mentor** to unstick you mid-problem without spoiling the answer
- **Business Scorecards stage** built specifically for the multi-CTE final-round questions that decide DA offers

*Catalogs help you drill. This collection trains you for the actual interview.*

LDS Data Analyst Interview Prep 75

About this collection

Your Learning Path

Why These 75?

A 7-Round Onsite Simulator

All 15 Industry Schemas

Business Scorecards — The Round That Decides Offers

Skill Coverage

FAQ

Ready to Master SQL?

LDS Data Analyst Interview Prep 75

About this collection

Your Learning Path