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Showing posts from September, 2014

Lessons I learned from SQL Interview

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So today I had a technical interview with a company in Seattle. It was my first technical interview after two months of job hunting in the west coast. I am writing this posts to remember what I made a mistake in SQL as people usually say we learn lessons from mistakes and failure.  First, About the rule that "GROUP BY function only allows you to SELECT two columns at a time".  Remark: This does NOT include the new column you generate by using COUNT!! Typical way you write a query with GROUP BY is like this: SELECT Column1, Column 2 FROM TableName GROUP BY Column1;  HOWEVER, if you want to COUNT something else besides Column 1 and Column 2, you can write: SELECT Column1, Column2, COUNT(Column3)  FROM TableName GROUP BY Column 1;  SQL will not generate the errors when you put the third elements "COUNT(Column3) before "FROM TableName GROUP BY Column1" because "COUNT(Column3)" is not considered as the third column in the "GROUP BY&quo

Tableau Annual Conference 2014

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Sep 8 to Sep 12, a huge data party took place in Convention Center in Seattle. It was an amazing week for any data enthusiasts from the data visualization industry. If you miss the conference, just search #data14 on Twitter or Instagram.  Monday Sep 8 Highlights of the Day: Lunch + Reception  I had a great lunch with Andy Kriebel , Bryan Brandon , and Alberto Cairo at the Cheesecake Factory just across the street of the Convention Center. It was my first meeting with the members from the Data Viz Team of Facebook !  Photo credits for Andy and Bryan. Andy shared his pictures on flickr. Check out here .  Reception began in the late afternoon with the warm welcoming music. The giant rectangle screen streamed the live Twitter and Instagram data.. (Yes, we are pretty nerdy :P)  At the reception, I had a great talk with the data viz professionals. I got to learn that Product Consultant at Tableau was not just a sales person but also a technician for the product. The Product