ORA-00937: - "not a single-group group function"
110987
Is there any difference between GROUP BY and DISTINCT
107680
How do I create a user-defined aggregate function?
63912
ORA-04031: unable to allocate bytes of shared memory ("","","","")
153827
Why the rows returns by "explain" is not equal to count()?
83406
''More than one row returned by a subquery used as an expression'' postgres error
50422
Can't list users - "select * from user" returns only one row with one column
155343
Select multiple (non-aggregate function) columns with GROUP BY
98720
SQL - using alias in Group By
126717
How to approach GROUP BY in PostgreSQL using Rails?
102054
Is there an Oracle SQL query that aggregates multiple rows into one row?
127084
Returning the 'last' row of each 'group by' in MySQL
43308
What is the difference between select count(*) and select count(any_non_null_column)?
59349
Simple SELECT statement fails with "syntax to use near", "ORA-00906", "syntax error at or near" or "syntax near the keyword"
1617
ORA-00979 not a group by expression
106227
Using column alias in WHERE clause of MySQL query produces an error
46432
What is the "N+1 selects problem" in ORM (Object-Relational Mapping)?
110417
What can go wrong using the same sequence across multiple tables in postgres?