Error using group by expression

Question

hello friends,
I use this query & used group by but oracle give error :
ORA-00979: not a GROUP BY expression
Select uu.ID,max(uu.module_name) as MainMenu,uu.NAME,decode(substr(param_str,4,1), 'P','ü','') as Allow,decode(substr(param_str,1,1), 'A','ü','') as Ins,decode(substr(param_str,2,1), 'E','ü','') as Edit,decode(substr(param_str,3,1), 'D','ü','') as Del from USER_MODULE uu,user1 where( user_name='SA'or user_name is null)and user1.srno=uu.srno and uu.ID=uu.ID group by uu.id,uu.name,MainMenu group by uu.id,uu.name

Answer 1

Hi
The 'param_str' in DECODE function either should be a bind variable for user input or should be a column of a table. If it is a table/view column then include it in the GROUP BY clause and the query should work.
If you specify a GROUP BY clause in a statement, then the select list can
contain only the following types of expressions:
– GROUP BY expressions
– Constants
– Aggregate functions and the functions USER, UID, and SYSDATE
– Expressions identical to those in the group_by_clause. If the group_by_
clause is in a subquery, then the GROUP BY columns of the subquery must
match the select list of the outer query. Any columns in the select list of the
subquery that are not needed by the GROUP BY operation are ignored without
error.
– Expressions involving the preceding expressions that evaluate to the same
value for all rows in a group
In short, except for the columns in aggregate functions, all columns must be included in the GROUP BY clause.
- Priya