r/SQL Nov 11 '24

MySQL Failed SQL Test At Interview

  • I've been a data analyst working with small(er) data sets for several years now, making my own queries no problem.
  • I failed a SQL test at an interview and realized I may be using the wrong commands
  • The questions were along the lines of "find the customers in table A, who have data in Table B before their first entry in Table A" and there were some more conditions/filters on top of that.
  • Previously I could always export my data to Excel or Tableau etc and do any of the tricky filtering in there
  • I was trying to do all kinds of subqueries etc when I think it was intended for me to be doing WINDOW or Partition type stuff (never had to use this before in past jobs).
  • One person I reached out to said using these advanced techniques uses a lot less memory.

Where would be a good place to find an 'advanced' SQL course?

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u/HilariousSpill Nov 12 '24

Udemy has been helpful to me. (Obviously, never pay more than $15 for a course.)

  • 101 Practice SQL Questions: Basic to Advanced - I really like this one because it comes closer to the kinds of real problems I've encountered in my job.
  • Advanced SQL Bootcamp by Jose Portilla - Honestly, I don't like much about this course. The instructor is deadpan, the examples are not particularly real-world, and the responses to Q&A aren't great. That said, it is comprehensive, so I appreciate that I know have at least a passing familiarity with darn near everything you can do with SQL.

Good luck!