How do you integrate data from multiple sources for analytics?

Integrating data from multiple sources for analytics involves combining datasets from different systems into a unified format for analysis. This typically starts by identifying the sources—such as databases, APIs, or flat files—and establishing pipelines to extract, clean, and load the data into a central repository. For example, a company might pull customer data from a CRM like Salesforce, transaction records from a PostgreSQL database, and web analytics from Google Analytics. The goal is to create a single source of truth that analysts can query without manually stitching datasets.

The next step is transforming the data to ensure consistency. This includes aligning schemas (e.g., renaming columns like “cust_id” and “customer_id” to a common format), resolving data type mismatches (e.g., converting strings to dates), and handling missing values. Tools like dbt (data build tool) or Python scripts are often used here. For instance, if one system stores dates as “MM/DD/YYYY” and another uses “YYYY-MM-DD,” a transformation step would standardize them. Data cleaning might also involve deduplication or aggregating metrics (e.g., summing daily sales into monthly totals). This phase ensures the integrated data is accurate and usable.

Finally, the transformed data is loaded into a storage system optimized for analytics, such as a data warehouse (e.g., Snowflake, BigQuery) or data lake (e.g., AWS S3). Engineers often automate these pipelines using workflow tools like Apache Airflow or Prefect to schedule updates. Data validation checks—such as verifying row counts or ensuring primary keys are unique—are added to catch errors. For example, a pipeline might flag if daily sales data from an e-commerce platform suddenly drops to zero, indicating a possible extraction issue. By automating and monitoring these steps, teams can maintain reliable, up-to-date analytics datasets.