What’s Your Favorite SQL Server Interview Question? Here’s Mine.

“Out of the stuff on your resume, what are you the proudest of, the most excited about?

When I’m interviewing a candidate for one of my clients, I’ll usually start with this question to help understand the resume. See, recruiters seem to actively encourage folks to keyword stuff their resume: to dump in everything and the kitchen sink, every task they’ve ever performed. Recruiters see the resume as a place to play Keyword Bingo.

Asking the candidate what they’re the proudest of is kinda like saying, “If you could set the font sizes in this resume, which phrases would be in bold, and which would you shrink down to tiny italics?”

It lets them pick their favorite topic, start geeking out, and open up to you.

If you’re the one asking the questions, there’s an important rule: you’re not allowed to correct them. All you can do is ask encouraging followup questions. Even if they say something completely outlandish, like “Cauliflowers are the root cause of forwarded CXPACKET,” you have to nod and say things like, “Do you remember how you first learned about that?” Forgive small missteps – interviewing is so stressful – but just start building a mental picture of their seniority level, what they love to do, and what might just be a keyword on their resume stuffed in by a recruiter.

What’s your favorite interview question?

Share yours in the comments. Don’t share the exact answer – I wouldn’t want people Googling this and getting all the answers – but feel free to type in the kinds of things you look for in a candidate’s answer (and maybe things you DON’T want to hear, too.)

I’ll host a live stream this afternoon and on Friday morning, and I’ll pick my favorites, and we’ll discuss ’em on my live stream.

  • Monday, April 20 at 4PM Eastern
  • Friday, April 24 at 9AM Eastern – download iCal

And then for May’s free training, I’m going to focus on database administration: I’ll do an updated live version of my DBA Job Interview Q&A Kit, and the recordings will be free all May long too:

Here’s the recording of Monday April 20th’s livestream:

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50 Comments. Leave new

  • So my favorite is my BS detector at the end. The first part of the interview is all describing their experience in various parts of technology, then at the end I ask them to rate themselves 1-10 on those same pieces of technology. I can’t tell you how many people have told me they don’t do Ssis or SSRS and yet rate themselves an 8 at the end. And anyone who rates themselves a 10 and thinks they know it all watch out.

    Reply
    • BZ – YEESSSS, I love letting folks rate themselves. It’s also a great question to let them regroup. I’ve seen folks exhale and then confess all kinds of things, and then be more truthful about where their skill levels are really at, and what they want to learn next.

      Reply
  • Monte Kottman
    April 20, 2020 7:57 am

    1 question that I had as applicant that still sticks with me is: “What is database filler?”

    I didn’t know the answer, and asked what it was. The manager replied, “It doesn’t exist, I wanted to find out if you would be honest about it”. At the time it made me pretty angry, but later I realized why that was important to him. Now I try ask questions in such a way that I can find out if they are honest about their knowledge.

    Having somebody be honest in their lack of knowledge is in some ways more important for their professional growth.

    Reply
    • Monte – hahaha, wow, I’ve never seen someone try that trick. I think I’d have reacted that same way you did the first time I heard it, heh.

      Reply
      • “Database filler”? I’m not familiar with that software. Could you explain more about this? Who is the vendor?

        That said, I’ve been asked how familiar I am with their software on site they’ve developed in house and exists only there.

        Reply
  • My favorite interview question has always one I’ve asked potential employers – “How do you feel about documentation?” Since I like to pick up small project based contract work on the side, I’ve found getting the answer to this question helps me prepare for whatever I’m about to get myself into. You’d be surprised at how telling this question can really be. I would even say its not bad as a question for an interviewer to ask either, but probably less valuable in that context.

    Reply
    • Doug – oh, that’s interesting for interviewers too. I should try asking it in a way that talks about what the candidate has done, like, “Tell me what you look for in good documentation,” or “Tell me how you document the scripts you write.”

      Reply
      • It def has potential – I bet you could easily get into the “personal OCD” topic about code indentation/styling. As an extension of that idea – you could easily steer the conversation in the direction of seeing how flexible they are as well, or what kind of personal habits they’ve developed (lol get it?)/maintained over the years. Even if the question is more of bridging piece to other topics, it certainly is a good one.

        Reply
  • I am fond of situational interviews. My favorite was four (4) example tickets (very real/ambiguous).
    while providing a commentary of what I was thinking, explaining what I was doing to a Jr. Dev.

    Reply
  • I have found that also asking them what is the one thing that they are least proud of as a followup to their proudest thing helps the candidate open up about any areas that they may feel weak in,

    Reply
    • Hiram – ooo, that’s interesting! We all have to do things we’re not proud of at work, or tasks we never want to drudge through again. That’ll also help show what a candidate wouldn’t be successful at (or wouldn’t enjoy.)

      Reply
  • For Senior + roles: “Tell me something about SQL Server I don’t already know.” I build up to that question with I’ve been doing DBA work for x decades so they know it can’t be something simple (and it seems to add a little stress which is also good to evaluate). I don’t really care what the answer is, but it usually tells me if they’re passionate about SQL and going deep into the technology.

    Reply
    • Shawn – HAHAHA, I would totally troll an interviewer on that one.”

      Me: “I bet you don’t know SQL Server’s default data file name is MDF.”

      Interviewer: “Yes, I knew that.”

      Me: “Oh, I’m surprised. You didn’t look too bright.”

      Reply
  • One “question” I always use is “Teach me something I don’t already know”. This does several things. It puts them on the spot to guess what I know, or don’t. It helps gauge how fast they are on their feet to extemporize (problem solving skills). It helps understand whether they can communicate their own complex ideas in an understandable way, which speaks to not only their thought processes, but also communication skills. You can be the smartest person in the room, but if you can’t communicate it to others, you’re pretty worthless…. to me.

    Reply
  • I have two go-to’s:

    1. Who are your favorite SQL authors?
    –> If they struggle to list one or two, they’re likely not well read. If they can rattle off 5 or more MVP’s/top authors with ease, it means they keep up to date with books/blogs/newsletters and are keen on keeping their skills up to date. This is a good sign.

    2. What’s the latest version of SQL you’ve used in production? 2016? Follow-up question: what features have you read about in 2017/2019 that you’re looking forward to trying?
    –>Again, trying to get a sense of whether it’s a candidate who keeps their skills up to date and is eager to learn, or someone who just goes through the motions.

    Reply
    • Mark – yeah, along that line, I also like asking, “When you Google something, what are the typical sites where you find results that work out well for you?” That tells me that they’re at least solving real problems. If they don’t know site names that turn up with answers, then they’re probably not actually researching the problems they’re facing.

      Reply
      • I once interviewed with a manager who firmly believed that a dba should know all the commands and syntax to use without using intellisense or google. There is not enough space in my brain for all that. And when I said I had no issue in looking up the info that was pretty much interview over.

        Reply
  • My focus has always been on finding out what sort of person they are more than understanding their tech skills. Tell me about a time you really struggled to collaborate with a co-worker and how you handled it kind of things. I figure I can teach tech skills or send them to training. I’m trying to figure out how they act under pressure, how they relate to other people, etc. Tough work for an interview, but hey, we work with what we’ve got 😉

    Reply
  • Mine would revolve a lot around database migrations and approach one takes for different severity applications. Rather than going into more technical stuff on how they do it, focus more on their strategy. For least critical and small databases most of the times backup/restores but when it comes to app with least downtime, its a great conversation how DBA/DEV/Management planning is done. This helps me if resource really understands the business and application in addition to some DBA activities when drill further with question like pre and post migration activities

    Reply
    • Kapil – that’s good! I like that a lot. Sometimes folks only have one answer, like shut down the server, copy the files, start it up on the new server. That helps inform you that they may not have worked on high availability apps before.

      Reply
  • My most useful question in terms of setting the candidates level of experience is “Everyone has been a part of a project that has failed. Without incriminating anyone, tell me why the project failed and in retrospect what you personally should have done to stop it from failing.” I should have worked harder is always a junior response.

    Reply
    • KD – oooo, that’s telling. I don’t know that I expect a lot of retrospective thinking from DBAs, but it would be really enlightening if someone had a good answer. That one even makes ME think!

      Reply
      • I do expect that.
        But
        Even from senior operational DBAs you should be able to get something like bad server migrations and a discussion of more proactive testing / monitoring and alerting. If you don’t have an answer for that, you aren’t even a mid level DBA. For those who say I don’t really work on projects I let them tune it to the worst thing that ever happened in production.

        I don’t need people who haven’t ever had something bad happen that they couldn’t have changed unless I’m hiring an intern / straight out of university type. Scars teach.

        Reply
  • I like to ask – “What is your approach to error handling?”

    I’m not looking for any certain answer – I’m asking to see if they HAVE an approach to error handling, and that it makes sense.

    Reply
    • Parker – WOW, OMG. I work with so many apps and I so rarely see any error handling at all. On a related note, I’ve asked developers how they handle deadlock errors, and that’s pretty enlightening too. Folks just rarely handle those – anyone with an answer sounds like a superstar.

      Reply
  • I always ask them to explain what is the difference between a view and a stored procedure. It’s amazing to me how many people don’t know. Of course, I most deal with db/application development rather than pure dba work.

    Reply
    • Adam – I like that because it tests not just the concept, but their ability to explain. If they can explain it, they’ll be a good mentor for others on their team.

      Reply
  • Where would you go looking for a problem to which you are not certain how to resolve? – here I would expect to hear some of the famous sites and names of SQL Gurus.
    Next I also expect to have a bit of comparison between older and newer versions of SQL, in terms of new features and improvements.

    Reply
    • I love that too. I love seeing their troubleshooting process, especially if it doesn’t involve saying, “I always ask my senior person for the answer.” Knowing when to Google versus when to escalate it to a senior person is a really valuable skill.

      Reply
  • What are 3 things in SQL Server you know exceptionally well, and 3 things you have very little experience with?

    Reply
  • When looking for devs, I’m fond of the screenshot question suggested here (https://www.brentozar.com/archive/2016/05/sql-interview-question-tell-see-screenshot/). I do it as a two-part:
    “What do you see here?” gets answers all over the board. Some struggle with the very simple join logic in the proc, and others start explaining the operations in the execution plan.
    The “What would you do if a user told you it was slow?” portion hasn’t been as useful yet–I’m still waiting for someone to investigate the nature of “slow”.

    Reply
  • the best question tells me what kind of person I am dealing with:

    what was your biggest issue with SQL Server in the last year (or 6 months) and what was your solution procedure “not the solution itself”

    Reply
  • One of my favorite questions : “Even though we try to be experts in databases, it’s impossible to know everything. Tell me about an aspect of databases you are still trying to learn.” I might throw out a few examples of speciality areas like replication or SSIS and then the move to more and more specialization within our field. I’m often surprise at the responses I received over the years. I’ve had more than one candidate tell me writing SQL queries.

    Reply
  • One of my favorite questions, what is your biggest mistake. Following up with the question what you’ve learned from that. The mistake itself isn’t all that interesting but it gives some insight if people are open about their mistakes. They happen, it really sucks but being honest about it rules. And from my perspective there’s no better teacher than failure.
    It was even in Batman Begins, so that has to be true!

    If anyone tells me they haven’t failed, they’re either lying or haven’t had a job before. And again, failure is fine. Be honest about it, pick up the pieces and learn from it.

    Reply
    • We ask the same thing. Anyone can make up a good disaster and recovery story, but when someone admits to a fault and gives you the proper corrective action he/she took, yep, that says a lot.

      Reply
    • I wouldn’t even consider hiring someone who hadn’t made a mistake. Bonus points for a MAJOR mistake! I have made several major mistakes once, not twice. I want to hire someone with some good “twice-shy” experience.

      Reply
  • 1. “How would you feel if asked to work with different than T-SQL dialect/RDBMS for 2-months project”

    2. “How to cap running total in SQL Server”
    For data: 1,5,7,2,9,8,3,1 and cap = 10
    Result:1,6,13,2,11,8,11,1

    Reply
  • I like to ask

    “What do you do when you don’t know what to do ?”

    Sometimes it requires a little follow up and encouragement that it’s ok to say Google it

    Then I get to learn how and where they learn.

    Another is the obvious

    It’s 3am, you are called with “The Production SQL Server is down” What do you do?

    Once that lead to a senior HR manager asking later is it really like that? to the IT something manager!

    Reply
    • Rob Again because he pressed submit to quickly
      April 22, 2020 2:06 am

      Follow up, when they say Senior Person, I say they are not available right now and this isn’t important enough to bother them.

      Also the second question is then a role playing game to see where they go which can be really interesting.

      Reply
    • Rob – ooo, I love the 3AM question! We used to do something similar in our interviews: we’d give them a broken VM and watch as they worked on troubleshooting it.

      Reply
  • I ask a similar question, “Which feature in the latest release looks the most promising?” This gives you a window into a person’s willingness to stay informed in a field that is constantly changing.

    Reply
  • My manager likes to ask an obscure question: You have a conference room how would you fill it with golf balls from floor to ceiling. Two rules:
    1. There are no wrong answers I just want your answer.
    2. You must think your answer verbally.

    He does this to understand how someone would think out an issue and dealing with ambiguity.

    Reply
    • I hate the holy hell out of dealing with those questions. (I had to sleep on this before writing my response.) It’s lazy, and it serves to let the manager introduce personal biases in the form of, “I just didn’t like the way they answered my question.”

      Reply
  • Brad Woodruff
    April 24, 2020 7:38 pm

    My favorite question is: at some point you will disagree with the boss. If you believe they are asking you do something unethical will you do it?

    Actually had a person say they never had a disagreement with their boss, yes they would do the task.

    I followed up with and if the boss asks you todo something illegal, would you do it?

    They answered “yes”.

    Let just ask we weren’t looking for a fall guy, but we found one…

    Reply
  • Andrew Brobston
    April 26, 2020 8:47 am

    We require mid-level and senior devs to have some level of SQL experience, preferably SQL Server. We don’t require expert-level familiarity, but we require senior devs to have significant depth in one relevant area, and many candidates claim SQL Server expertise. So, I want to see if those candidates can back it up.

    I’ll ask a basic, open-ended question that I don’t want to give away here. Based on the answer, which often as not is way off the mark, I will ask the candidate to tell me what a term they used means. A common one is, “You said you would check the clustered index. What is a clustered index, and how would you check it?” (That’s a strange and basically wrong answer, but I have heard it several times.) When the candidate can’t tell me, we’re pretty much done. I’ve had people claim two decades of experience who couldn’t tell me that. I only ask about terms they used; this isn’t a trivia quiz.

    If someone doesn’t claim to be an expert, I don’t expect them to be. But, we had a candidate claiming that databases were a weak area, maybe not good enough for senior level. That candidate blew most “expert” candidates out of the water and is now on my dev team.

    Reply

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