SQL Server Interview Topic 26: Analytics-Style Queries
This topic checks whether you can turn data into useful information. Many dashboards need trends, percentages, comparisons, and top lists.
You should be able to explain analytical query requirements in simple steps.
Q165. How do you calculate percentages in SQL reports?
Quick interview answer:
Use aggregate values and calculate one value as part of another. For example, pass percentage can be pass count divided by total student count multiplied by 100. Be careful with division by zero.
Study in detail: Math Functions and CASE and Aggregate Functions - These lessons explain calculations.
Q166. How do you compare this month vs last month?
Quick interview answer:
Filter data by date ranges for each month, group results, and compare totals. Date functions help identify month and year, but the query should handle year changes correctly.
Study in detail: Date Functions and Reporting and Dashboard Scenarios - These lessons explain report filters.
Q167. How do you find top N records per group?
Quick interview answer:
Use ROW_NUMBER or RANK with PARTITION BY group column and order by the score or amount. Then filter the ranking result. This is useful for top students in each class.
Study in detail: Window Functions - This article explains ranking per group.
Q168. How do you show trend data?
Quick interview answer:
Group records by time period, such as day, month, or year, and calculate totals for each period. Trend reports are common for attendance, fees, admissions, and exam results.
Study in detail: GROUP BY and HAVING and Date Functions - These lessons explain grouped date reports.
Q169. How do you explain analytics queries in interviews?
Quick interview answer:
Start with the business question, then explain the needed tables, filters, grouping, calculations, and output. Analytics SQL is not only syntax; it is about answering a useful question from data.
Study in detail: Complex Business Logic - This lesson explains real business query thinking.
For analytics questions, say the business meaning of the query before the SQL feature.