Do all columns in a SELECT list have to appear in a GROUP BY clause

by

Imagine the following:

    A    B    C
   Cat   10   False
   Dog   25   True
   Dog   20   False
   Cat   5    False

If you select A, B and Group By Only A – what would your output be? You’d only have two rows (or tuples) because you have two values for A – but how does it display B?

If you group by A, B, you’d get four rows, no problems there.
If you group by A and perform a function on B – like SUM(B) then you get two rows again:

    Cat    15
    Dog    45

But if you select A, B and only group by A – it doesn’t know what to do. Truthfully, I believe there are some databases out there that will select a random value for B in that case and I believe there are some that will give you an error message.

More Related Contents:

  1. The most efficient way to UPPER CASE two columns in a single query [closed]
  2. SQL query to get rows by comparing data in different columns
  3. How to calculate age (in years) based on Date of Birth and getDate()
  4. Does the join order matter in SQL?
  5. Case insensitive searching in Oracle
  6. Combining “LIKE” and “IN” for SQL Server [duplicate]
  7. Is there a shortcut for SELECT * FROM?
  8. sql statement error: “column .. does not exist”
  9. How to get difference between two rows for a column field?
  10. SQL Server SELECT into existing table
  11. Rewriting mysql select to reduce time and writing tmp to disk
  12. Sorting null values after all others, except special
  13. Can I do a max(count(*)) in SQL?
  14. Which SQL query is better, MATCH AGAINST or LIKE?
  15. SQL Server: drop table cascade equivalent?
  16. How to kill a running SELECT statement
  17. SPARK SQL – case when then
  18. Why postgres returns unordered data in select query, after updation of row?
  19. How do I convert a “legacy” left outer join statement in Oracle?
  20. Ad hoc queries vs stored procedures vs Dynamic SQL [closed]
  21. Comparing with date in Oracle sql
  22. HAVING without GROUP BY
  23. IN Clause with NULL or IS NULL
  24. SQL selecting rows by most recent date with two unique columns
  25. Insert Update stored proc on SQL Server
  26. TSQL – How to use GO inside of a BEGIN .. END block?
  27. What does ON [PRIMARY] mean?
  28. MySQL SELECT x FROM a WHERE NOT IN ( SELECT x FROM b ) – Unexpected result
  29. selecting top N rows for each group in a table
  30. Getting warning: Null value is eliminated by an aggregate or other SET operation

Leave a Comment