Incorrect GROUP BY

Revision as of 11:47, 19 July 2012 by Connor (talk | contribs)
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When using a GROUP BY clause every field in the SELECT list must be either:

  • One of the GROUP BY terms - in this case region
  • An aggregate function - for example SUM or COUNT
  • An expression based on the above

In the example the field name may not be used on the SELECT line.

In a group by line each region shows up only once - however in a typical region such as Africa there are several different name values. WHich one should SQL pick?


  • Remove the offending field from the SELECT line
  • Add the field to the GROUP BY clause
  • Aggregate the offending field
SELECT name, region, MAX(population)
  FROM bbc
  GROUP BY region