04 Try it yourself Interactive

Seven rows, three buckets, two answers

The same seven rows and the same query, one clause per press. The table on screen is the query’s working set at that instant, so watch its shape change: rows, then rows with a bucket label, then one line per bucket, then the answer. Amber marks what the current clause is looking at, rose marks what it just threw away, green is final. Two tabs: GROUP BY course is the query from section 02, and GROUP BY course, term drops the WHERE clause and groups on both columns instead. Nothing plays on its own. Next, Back and Reset, or the arrow keys.

One grouping column
mark · 7 rows
Watch the two count columns when the CSE bucket appears. It holds three rows and two marks, and no other bucket in the table has that problem.
Press Next to begin. Each press runs one clause.


      

        
Rows in play–

        
Buckets–

        
Rows in the answer–

        
Rows discarded0

      


      

      

        
        
        
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