Look For Something Ridiculous, Not Test-Takers

December 23, 2017 / Matt / Leave a comment

Look for something ridiculous? Not that long ago I used to think that the best interview questions were one where the candidate could answer the question in many different but accurate ways, rather than just one perfect way. Which, at the time, would have weeded out many incompetent colleagues, consultants, and managers. It seemed fool-proof!

Fast forward to today, after much more experienced in interviewing and matured in my expectations of nervous people. These people are just people – they just mostly suck. Like, foundationally terrible candidates, four out of every five. The cure is that while they may not perform like you expect, they may show other signs – much like how I thought the ability to Open Notepad was a single testament to skill – there is one great trait to look for: Passionate Interest! No matter the questions you ask a candidate if they get excited, geeky, inspired, passionate about the answer, then you’ve got something special.

My argument here is that one who would answer the questions the way you’d ideally-expect versus someone who may underperform, yet still be a contender, will still be equally expressive in a positively geeky way. While the true underperformers will break down in many obvious ways, the common denominator between them will undoubtedly be their disdain for coming to a solution; An eagerness to say something, rather than feeling something. These are the simple clues to look for. Look for something ridiculous and genuine. These are the people who will be there to bounce ridiculous ideas off of and fuel the team.

Nobody wants to work on a team where people only share details when you ask for them. I want to work on teams where people share information because they think it will be helpful even though you didn’t ask for it.

Interview Question | Weed Out Non Technical Candidates

October 1, 2016 / Matt / Leave a comment

Weed out non technical candidates by asking how to open notepad.

I’ve since evolved a little since I posted this and would like to hone my focus of this post to a clearer target: Look For Ridiculous instead.

This is my hands-down, go-to interview question to weed out non-technical candidates. I have had such great success with this interview question and have shared it with other colleagues who have experienced equal success that I think it deserves a place on this blog. I’ve talked about this before, a little over a year ago is when I made my first public announcement of my new-found favorite interview question:

How do you open notepad on windows?

I typically preface the question with a short disclaimer like, “This question is a bit unorthodox and there really isn’t a wrong answer, having more than one answer is also equally acceptable…” This sets the stage for the actual question which I’ll phrase like “On a windows machine, regardless of version specifics, how do YOU open windows notepad?”

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Interview Question | How to find all duplicates in a table?

September 17, 2016 / Matt / Leave a comment

One of my favorite interview questions is to hand the candidate a marker and ask them to write out how to find all duplicates in a table. This should be straightforward and weeds out anyone who struggles with SQL; and even if they don’t struggle with SQL, this will be a good way to gauge where they’re at. But, it doesn’t stop there!

I’ve since evolved a little since I posted this and would like to hone my focus of this post to a clearer target: Look For Ridiculous instead.

After they successfully give an answer, typically one involving grouping by the business key having a count greater than one, which I’ll show in the first example below, that is a go-to correct response to this question. But, I throw them a curve ball, I’ll say “Great! Show me another way.” Then, I ask for another, and another, and another… ~~with great power comes great responsibility~~ being the interviewer is nefariously fun!

So, let’s take a look at some ways on how to find all duplicates in a table by exploring all the ways that I’ve come up with. Here’s our test data we’ll be working with, which has 2 sets of duplicates:


CREATE TABLE FACT_ORDERS (
  CUSTOMER_KEY INTEGER,
  ORDER_DATE_KEY INTEGER,
  ORDER_AMOUNT DECIMAL(15,2),
  ETL_LOAD_DATE DATE
 );

INSERT INTO FACT_ORDERS SELECT 1, 20160901, 812.19, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 4, 20160901, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 3, 20160901, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 4, 20160902, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 3, 20160901, 123.46, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 2, 20160901, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 3, 20160901, 123.46, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 1, 20160902, 812.19, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 1, 20160901, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 2, 20160901, 5169.23, CAST('2016-09-17' AS DATE);
INSERT INTO FACT_ORDERS SELECT 2, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

CREATE TABLE FACT_ORDERS (

CUSTOMER_KEY INTEGER,

ORDER_DATE_KEY INTEGER,

ORDER_AMOUNT DECIMAL(15,2),

ETL_LOAD_DATE DATE

);

INSERT INTO FACT_ORDERS SELECT 1, 20160901, 812.19, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 4, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 3, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 4, 20160902, 5169.23, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 3, 20160901, 123.46, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 2, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 3, 20160901, 123.46, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 1, 20160902, 812.19, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 1, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

INSERT INTO FACT_ORDERS SELECT 2, 20160901, 5169.23, CAST('2016-09-17' AS DATE);

The goal is to learn how to find all the duplicates in a table and return only 2 rows of data, ie: that have more than one identical row, even though there are 5 rows of duplicates (three dupes of one row and two of another).

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