You can order a specific column in a query by adding ORDER BY clause, but the result always returns and lists all the rows that some of them may not be needed. Actually, the meaningful rows could be the first few rows in a decision making process, the others could be nonsense information. For MySQL, which can use LIMIT clause to limit the number of returned rows, but Oracle can not.
Here is an example to list only meaningful rows which may be top 5 or top 10 rows. In this case, we would like to know the total number of objects by owner and object types.
SQL> set pagesize 50;
SQL> column owner format a15;
SQL> column object_type format a20;
SQL> select owner, object_type, count(*) total from dba_objects group by owner, object_type order by 3 desc;
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
PUBLIC SYNONYM 27724
SYS JAVA CLASS 20444
SYS VIEW 3763
ORDSYS JAVA CLASS 1898
SYS TYPE 1306
SYS INDEX 996
SYS TABLE 969
SYSMAN INDEX 953
APEX_030200 INDEX 946
SYS JAVA RESOURCE 760
SYSMAN TABLE 729
SYSMAN TYPE 678
SYS PACKAGE 623
SYS PACKAGE BODY 597
MDSYS JAVA CLASS 531
SYSMAN VIEW 471
ORDSYS TYPE 446
APEX_030200 TRIGGER 366
APEX_030200 TABLE 360
XDB LOB 340
SYS JAVA DATA 328
OLAPSYS VIEW 307
SYSTEM INDEX 210
SYSMAN PACKAGE 196
SH INDEX PARTITION 196
SYSMAN PACKAGE BODY 196
APEX_030200 PACKAGE 189
APEX_030200 PACKAGE BODY 181
MDSYS TYPE 157
SYSTEM TABLE 156
APEX_030200 LOB 155
SYS LOB 153
SYS LIBRARY 144
OLAPSYS INDEX 135
SYS SEQUENCE 134
ORDDATA INDEX 129
XDB INDEX 128
OLAPSYS TABLE 126
APEX_030200 VIEW 125
MDSYS TABLE 123
MDSYS INDEX 114
SYS TYPE BODY 113
WMSYS VIEW 110
MDSYS FUNCTION 107
SYS PROCEDURE 101
SYS FUNCTION 98
XDB TYPE 97
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
SYSMAN TRIGGER 97
MDSYS LOB 94
MDSYS VIEW 86
XDB TABLE 81
SYSMAN LOB 75
ORDDATA TABLE 73
CTXSYS PACKAGE 73
CTXSYS VIEW 71
MDSYS PACKAGE 70
ORDSYS JAVA RESOURCE 70
MDSYS PACKAGE BODY 66
CTXSYS PACKAGE BODY 62
WMSYS INDEX 61
EXFSYS VIEW 56
SH TABLE PARTITION 56
CTXSYS INDEX 56
MDSYS TRIGGER 53
XDB XML SCHEMA 52
SYS INDEX PARTITION 52
SYSTEM INDEX PARTITION 52
SYSMAN TYPE BODY 49
SYS TABLE PARTITION 49
OLAPSYS TRIGGER 48
EXFSYS TABLE 47
EXFSYS JAVA CLASS 47
CTXSYS TABLE 47
WMSYS TABLE 45
OLAPSYS PACKAGE 45
APEX_030200 SYNONYM 45
MDSYS TYPE BODY 43
OLAPSYS PACKAGE BODY 43
SYSTEM TABLE PARTITION 39
EXFSYS INDEX 39
OE TYPE 37
XDB PACKAGE 34
OE INDEX 33
XDB PACKAGE BODY 33
ORDSYS FUNCTION 32
CTXSYS TYPE 31
EXFSYS TYPE 30
ORDSYS PACKAGE 28
SH INDEX 27
XDB TRIGGER 27
EXFSYS FUNCTION 26
DBSNMP TABLE 25
ORDDATA VIEW 25
SYS CONSUMER GROUP 25
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
MDSYS OPERATOR 25
WMSYS PACKAGE 22
WMSYS PACKAGE BODY 22
SYSTEM LOB 22
ORDSYS PACKAGE BODY 20
SYSTEM SEQUENCE 20
APEX_030200 PROCEDURE 19
SYS PROGRAM 19
HR INDEX 19
EXFSYS PACKAGE 18
EXFSYS PACKAGE BODY 18
MDSYS LIBRARY 18
PM LOB 17
XDB LIBRARY 17
SH TABLE 17
IX TABLE 17
SYS QUEUE 17
OE LOB 15
ORDSYS TYPE BODY 15
MDSYS SEQUENCE 15
IX INDEX 14
WMSYS TYPE 14
OE TABLE 14
SYSMAN SEQUENCE 13
OE VIEW 13
DBSNMP INDEX 13
SYS JOB CLASS 13
SYS RULE SET 13
ORDDATA SEQUENCE 12
SYSMAN FUNCTION 12
OWBSYS_AUDIT SYNONYM 12
APEX_030200 FUNCTION 12
SYSMAN QUEUE 12
SYSTEM VIEW 12
EXFSYS PROCEDURE 10
SYS TRIGGER 10
SYS JOB 10
SYS CLUSTER 10
SYS RESOURCE PLAN 10
WMSYS OPERATOR 9
SYS WINDOW 9
HR TABLE 9
SYS UNDEFINED 9
SYS SYNONYM 9
WMSYS SEQUENCE 9
SYS EVALUATION CONTEXT 9
ORDDATA LOB 9
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
IX VIEW 8
SYS DIRECTORY 8
WMSYS LOB 8
SI_INFORMTN_SCH SYNONYM 8
EMA
DBSNMP TYPE 8
BI SYNONYM 8
SYSTEM SYNONYM 8
XDB FUNCTION 7
XDB OPERATOR 7
OLAPSYS TYPE 7
ORDSYS PROCEDURE 7
SYS CONTEXT 7
DBSNMP VIEW 7
SYS OPERATOR 7
CTXSYS TYPE BODY 6
CTXSYS OPERATOR 6
OE SYNONYM 6
EXFSYS TRIGGER 5
ORDSYS VIEW 5
FLOWS_FILES SYNONYM 5
XDB VIEW 5
OLAPSYS SEQUENCE 5
SH DIMENSION 5
XDB SEQUENCE 5
ORDSYS TABLE 5
XDB TYPE BODY 5
ORDPLUGINS PACKAGE 5
ORDPLUGINS PACKAGE BODY 5
EXFSYS TYPE BODY 5
DBSNMP PACKAGE 4
OE TRIGGER 4
SYSTEM QUEUE 4
SYSMAN RULE SET 4
FLOWS_FILES INDEX 4
APEX_030200 SEQUENCE 4
SYS SCHEDULER GROUP 4
CTXSYS INDEXTYPE 4
ORDSYS INDEX 4
SCOTT TABLE 4
DBSNMP PACKAGE BODY 4
WMSYS PROCEDURE 4
XDB PROCEDURE 4
IX QUEUE 4
OUTLN INDEX 4
PM INDEX 4
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
WMSYS FUNCTION 4
APEX_030200 TYPE 4
IX RULE SET 4
IX LOB 3
CTXSYS SEQUENCE 3
ORACLE_OCM PACKAGE 3
PM TABLE 3
SYSMAN PROCEDURE 3
ORACLE_OCM PACKAGE BODY 3
MDSYS JAVA RESOURCE 3
PM TYPE 3
SYS SCHEDULE 3
HR SEQUENCE 3
OE TYPE BODY 3
OUTLN TABLE 3
SH LOB 2
SYSTEM TRIGGER 2
HR PROCEDURE 2
OLAPSYS LOB 2
EXFSYS JOB 2
CTXSYS LOB 2
MDSYS PROCEDURE 2
WMSYS RULE SET 2
ORDSYS LIBRARY 2
ORACLE_OCM JOB 2
WMSYS TRIGGER 2
SH MATERIALIZED VIEW 2
SCOTT INDEX 2
SYSMAN EVALUATION CONTEXT 2
CTXSYS FUNCTION 2
DBSNMP SEQUENCE 2
CTXSYS PROCEDURE 2
EXFSYS LOB 2
SYS DESTINATION 2
WMSYS QUEUE 2
IX SEQUENCE 2
IX EVALUATION CONTEXT 2
MDSYS INDEXTYPE 2
SYS JAVA SOURCE 2
APPQOSSYS TABLE 2
XDB INDEXTYPE 2
HR TRIGGER 2
FLOWS_FILES TABLE 1
OWBSYS INDEX 1
SYSTEM PACKAGE 1
WMSYS EVALUATION CONTEXT 1
EXFSYS INDEXTYPE 1
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
APPQOSSYS SYNONYM 1
SYSTEM PROCEDURE 1
EXFSYS JAVA RESOURCE 1
SYS LOB PARTITION 1
SYSTEM TYPE 1
OUTLN LOB 1
SYS EDITION 1
EXFSYS SEQUENCE 1
EXFSYS OPERATOR 1
EXFSYS LIBRARY 1
DBSNMP SYNONYM 1
IX TYPE 1
OE SEQUENCE 1
SYSMAN MATERIALIZED VIEW 1
CTXSYS LIBRARY 1
WMSYS TYPE BODY 1
DBSNMP PROCEDURE 1
SYSTEM PACKAGE BODY 1
OLAPSYS FUNCTION 1
SH VIEW 1
OE FUNCTION 1
OWBSYS TABLE 1
FLOWS_FILES LOB 1
OUTLN PROCEDURE 1
HR VIEW 1
SYS RULE 1
FLOWS_FILES TRIGGER 1
260 rows selected.The result returns all the rows. There could be too many unwanted information to mislead your decision. Let's trim the result by comprising the original query into a subquery and then limit the rows returned by a pseudo column ROWNUM.
SQL> select * from (select owner, object_type, count(*) total from dba_objects group by owner, object_type order by 3 desc) where ROWNUM <= 10;
OWNER OBJECT_TYPE TOTAL
--------------- -------------------- ----------
PUBLIC SYNONYM 27724
SYS JAVA CLASS 20444
SYS VIEW 3763
ORDSYS JAVA CLASS 1898
SYS TYPE 1306
SYS INDEX 996
SYS TABLE 969
SYSMAN INDEX 953
APEX_030200 INDEX 946
SYS JAVA RESOURCE 760
10 rows selected.