DP-900 Describe an analytics workload on Azure Practice Question
A financial services company uses Azure Synapse Analytics to process large volumes of transaction data. They have a dedicated SQL pool (formerly SQL DW) that ingests curated, aggregated data nightly from a data lake. Data analysts need to run ad-hoc, exploratory T-SQL queries on raw transaction data stored as Parquet files in Azure Data Lake Storage Gen2. These queries vary widely in complexity and frequency. The company wants to minimize costs for these ad-hoc queries while still using full T-SQL capabilities. Which approach should they recommend?
⚠ Common exam trap
Test-takers frequently confuse external tables in a dedicated SQL pool with serverless SQL pool, assuming both are equally cost-effective, but they overlook that dedicated SQL pool incurs fixed compute costs regardless of usage, while serverless SQL pool is truly pay-per-query.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a serverless SQL pool endpoint to query the data lake directly.
Serverless SQL pool in Azure Synapse Analytics is designed for ad-hoc, on-demand querying of data lake files (like Parquet) without provisioning or paying for dedicated compute resources. It supports full T-SQL syntax and charges only for the data processed per query, making it cost-effective for exploratory workloads with variable complexity and frequency.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use external tables in the dedicated SQL pool to query the data lake directly.
Why it's wrong here
While external tables in a dedicated SQL pool can indeed query files in the data lake without copying them into the pool, the dedicated pool's compute nodes are provisioned around the clock unless you manually pause the SQL pool. That ongoing hourly billing is wasted if queries are only ad-hoc and infrequent, even if the amount of data scanned is small. A serverless SQL pool would provide the same external-file access with zero predictable fixed costs, making this approach wrong because it optimizes storage over the much larger, constant compute cost.
When this WOULD be correct
If the company needed to combine raw data from the data lake with curated data already in the dedicated SQL pool in a single query, and the dedicated SQL pool was already active for other workloads, external tables would allow seamless joins without moving data.
- ✓
Create a serverless SQL pool endpoint to query the data lake directly.
Why this is correct
Creating a serverless SQL pool endpoint lets you issue standard T-SQL queries directly against Parquet, JSON, CSV, or other files in the data lake using OPENROWSET or external tables, with compute resources dynamically spawned only while a query is executing. Because billing is per byte of data scanned rather than per minute of provisioned capacity, the service auto-scales to the query at hand and is ideal for sporadic, ad-hoc exploration. There is no need to ingest or transform data first, so analysts can run immediate exploratory queries with full T-SQL projection, filtering, and joins across lake files.
- ✗
Load the raw data into the dedicated SQL pool before querying.
Why it's wrong here
Physically loading the raw data into a dedicated SQL pool first introduces a COPY/PolyBase ingestion pipeline, creates duplicate storage in the pool, and requires compute resources to perform the load itself. For data that is queried only occasionally, the combined cost, complexity, and maintenance of keeping that raw data synchronized outweighs any query performance gain. This approach also delays analysis until ingestion completes and risks querying stale copies if the lake files change, so it is poorly suited to ad-hoc exploration where direct file reads are simpler and more current.
When this WOULD be correct
This option would be correct if the company required frequent, high-performance queries on the raw data, and the data volume was manageable within the dedicated SQL pool's storage, or if the queries needed to join raw data with the curated data in the pool frequently.
- ✗
Use Azure Data Explorer to query the data lake.
Why it's wrong here
Azure Data Explorer is optimized for interactive analytics on large volumes of streaming and time-series data, but it uses a Kusto query language (KQL), not T-SQL, and is not the best fit for general T-SQL ad-hoc queries.
When this WOULD be correct
A company needs to run high-performance, interactive queries on large volumes of streaming telemetry data (e.g., IoT sensor logs) with low latency, and they are comfortable using Kusto Query Language (KQL) instead of T-SQL. They prioritize speed and scalability over full T-SQL compatibility.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The DP-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Create a serverless SQL pool endpoint to query the data lake directly.Correct answer▾
Why this is correct
Creating a serverless SQL pool endpoint lets you issue standard T-SQL queries directly against Parquet, JSON, CSV, or other files in the data lake using OPENROWSET or external tables, with compute resources dynamically spawned only while a query is executing. Because billing is per byte of data scanned rather than per minute of provisioned capacity, the service auto-scales to the query at hand and is ideal for sporadic, ad-hoc exploration. There is no need to ingest or transform data first, so analysts can run immediate exploratory queries with full T-SQL projection, filtering, and joins across lake files.
✗Use external tables in the dedicated SQL pool to query the data lake directly.Wrong answer — click to see why▾
Why this is wrong here
External tables in a dedicated SQL pool require the pool to be running and incur compute costs even when idle, making them cost-inefficient for ad-hoc, infrequent queries on raw data. Serverless SQL pool is pay-per-query and better suited for this scenario.
★ When this WOULD be the correct answer
If the company needed to combine raw data from the data lake with curated data already in the dedicated SQL pool in a single query, and the dedicated SQL pool was already active for other workloads, external tables would allow seamless joins without moving data.
Why candidates choose this
Candidates may assume that any T-SQL query on data lake files requires external tables, and they might overlook the cost implications of keeping a dedicated SQL pool running for sporadic queries.
✗Load the raw data into the dedicated SQL pool before querying.Wrong answer — click to see why▾
Why this is wrong here
Loading raw data into the dedicated SQL pool incurs storage and compute costs for data that is only queried ad-hoc, and the dedicated SQL pool is optimized for curated, aggregated data, not raw exploratory queries.
★ When this WOULD be the correct answer
This option would be correct if the company required frequent, high-performance queries on the raw data, and the data volume was manageable within the dedicated SQL pool's storage, or if the queries needed to join raw data with the curated data in the pool frequently.
Why candidates choose this
Candidates may think loading data into the dedicated SQL pool is necessary to use T-SQL, or assume that the pool's performance is always better, overlooking the cost and suitability for ad-hoc workloads.
✗Use Azure Data Explorer to query the data lake.Wrong answer — click to see why▾
Why this is wrong here
Azure Data Explorer (ADX) is optimized for interactive analytics on large volumes of streaming and time-series data, not for full T-SQL capabilities. The question requires full T-SQL support for ad-hoc queries, which ADX does not provide (it uses KQL).
★ When this WOULD be the correct answer
A company needs to run high-performance, interactive queries on large volumes of streaming telemetry data (e.g., IoT sensor logs) with low latency, and they are comfortable using Kusto Query Language (KQL) instead of T-SQL. They prioritize speed and scalability over full T-SQL compatibility.
Why candidates choose this
Candidates may associate Azure Data Explorer with fast querying of large datasets in data lakes, overlooking that it does not support T-SQL and is designed for different query patterns (time-series, logs) rather than general-purpose SQL analytics.
Analysis generated from the official DP-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
Go deeper
Related to this question
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Data Roles and Core Concepts
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
Key term
Serverless SQL pool
Serverless SQL pool is an on-demand, pay-per-query analytics service in Azure that lets you query data stored in data lakes without provisioning or managing any dedicated infrastructure.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-900 exam.