Oracle/PLSQL: ORA-00937 Error
ORA-00937: not a single-group group function
Cause of Error
The option(s) to resolve this Oracle error are:
Rewrite the SELECT statement so that the column or expression listed in the SELECT list is also found in the GROUP BY clause.
Remove the expression from the SELECT list that was not in the GROUP BY clause.
For example, if you had tried to execute the following SELECT statement:
SELECT department, MIN(salary) as "Lowest salary" FROM employees;
You would receive the following error message:
You could correct this by including department in the GROUP BY clause as follows:
SELECT department, MIN(salary) as "Lowest salary" FROM employees GROUP BY department;