I have attempted DP-900 Exam on 05th October 2020. and cleared the exam with 850 marks. Here is my preparation guide. The below-provided materials are enough to clear this exam with a flying score.
You have to be clear in below topics
i) Data, visualization, Types of charts
ii) Relational Database
* SQL on Virtual Machine * Azure Managed instance * Azure SQL database * Azure Mysql database * Azure Postgres database * Azure MariaDB
iii) Non-Relational Database (NoSQL)
* Azure Cosmos DB * Azure Table Storage * Azure Document DB * Graph Database * Column Database * Blob Storage
iv) OLTP vs OLAP
v) Azure synapse database, Azure DataLake
vi) Data factory, Databricks
vii) PowerBi (just an overview of it and its services)
1) Microsoft Learning Path for DP-900
2) Scott Duffy DP-900 course on udemy
3) Exam topics practise tests.
These 3 resources are enough to excel in your exam.
Good Luck and all the very best!!