Eine Einführung in


Error 7 ERROR: Attribute xxx.xxx must be GROUPed or used in an aggregate function



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

Specific to PostgreSQL