SQL for BI Reporting

Context

Many analytics and business intelligence roles rely on SQL even when dashboards are built in tools like Tableau, Power BI, or Looker. Interviewers ask this question to understand whether you can connect raw data to decision-ready reporting.

Core question

Describe your experience using SQL alongside data analytics or BI tools. Explain how you used SQL to prepare data, validate metrics, and support dashboards or recurring reports. Discuss the types of queries you wrote, such as filtering, aggregations, grouping, and basic data cleanup.

Scope guidance

Keep your answer practical rather than theoretical. The interviewer is usually looking for evidence that you can use SQL to answer business questions, create reliable datasets for reporting, and work effectively with analysts or dashboarding tools. Mention the kinds of metrics you analyzed, how you ensured accuracy, and how SQL fit into your broader analytics workflow.

SQL as the foundation for BI

BI tools often sit on top of SQL queries, views, or modeled tables. Even when a dashboard is built visually, SQL is commonly used to define metrics, filter records, and shape the data before it reaches the reporting layer.

SELECT department, COUNT(*) AS employee_count
FROM employees
GROUP BY department;

Aggregations for reporting

A large share of BI work involves summarizing detailed records into business metrics. SQL aggregations such as COUNT, SUM, AVG, MAX, and MIN are essential for building KPI tables and validating dashboard numbers.

SELECT report_month, SUM(revenue) AS total_revenue
FROM monthly_sales
GROUP BY report_month;

Data preparation and cleanup

Before data is useful in a dashboard, it often needs filtering, standardization, and null handling. SQL is frequently used to remove invalid rows, replace missing values, and create cleaner reporting datasets.

SELECT employee_name, COALESCE(region, 'Unknown') AS region
FROM employees
WHERE status = 'active';

Metric validation

Strong analytics work includes checking whether dashboard outputs match the underlying source data. SQL helps validate totals, compare record counts, and confirm that business definitions are applied consistently.

SELECT COUNT(*) AS active_customers
FROM customers
WHERE is_active = TRUE;