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Posted by Aquib Javed
Aquib Javed
8,289 Points

What is the specific usage of the group by clause in SQL?

From W3 and some other search results, what I learned is, 'group by' summarizes an output, as in instead of showing a number of different results, it shows them in one particular output. What I don't understand is, when is it actually necessary to use the clause?

1 Answer

Product Team
Product Team
6,835 Points
Product Team
Product Team
6,835 Points

I'm fairly new to SQL, but my understanding is that it "rolls-up" or merges rows. For example, you have the following rows:

Country | Points

  • USA 12
  • Canada 6
  • USA 18

Group By country would roll this up to

Country | Points

  • USA 30
  • Canada 6

I'm guessing I'm describing this poorly, but it is how I use it.