Query Dojo

SQL SELECT and Filtering Interview Questions

Screening rounds often start here: selecting the right columns, filtering the right rows and handling NULLs and dates correctly.

These questions are short, but each one hides a detail interviewers check, like NULLs that a plain comparison silently skips.

Patterns to know

  • Filtering with WHERE, IN, BETWEEN and LIKE
  • Handling NULL with IS NULL and COALESCE
  • Conditional labels with CASE WHEN
  • Date math and string functions

Easy questions

  1. Easy Employees Hired in the Last 90 Days New Hire Onboarding List Free
  2. Easy Combine Two Tables With UNION Merge Active and Inactive Users Free
  3. Easy Completion Rate as a Percentage Course Completion Percentage Free
  4. Easy Employees Without a Manager Employees Without Managers Free
  5. Easy Search by Name Pattern With LIKE Search Products by Name Pattern Free
  6. Easy Days Between Two Dates Calculate Account Age in Days Free
  7. Easy Convert Seconds to Minutes Convert Track Duration to Minutes Free
  8. Easy Salaries Over $100,000 Six-Figure Earners Free
  9. Easy Filter a Price Range With BETWEEN Mid-Range Product Filter Free
  10. Easy Replace NULL With COALESCE Handle Missing Data with COALESCE Free
  11. Easy Salary Bands With CASE WHEN Classify Employees by Salary Tier Free

Hard question

  1. Hard Inventory Reorder Point Calculate Reorder Point for Inventory Premium

More SQL interview topics

SQL Window Function Interview QuestionsSQL JOIN Interview QuestionsSQL GROUP BY Interview QuestionsSQL Subquery Interview QuestionsSQL CTE Interview QuestionsSQL INSERT, UPDATE and DELETE Interview QuestionsSQL Transaction Interview Questions