Oracle PL/SQL/Analytical Functions/NULLs First
Control whether nulls are the highest or lowest in a group using NULLS FIRST
<source lang="sql">
SQL> CREATE TABLE all_sales (
2 year INTEGER, 3 month INTEGER, 4 prd_type_id INTEGER, 5 emp_id INTEGER , 6 amount NUMBER(8, 2) 7 );
Table created. SQL> SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,1 ,1 ,21 ,16034.84);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,2 ,1 ,21 ,15644.65);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,3 ,2 ,21 ,20167.83);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,4 ,2 ,21 ,25056.45);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,5 ,2 ,21 ,NULL);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,6 ,1 ,21 ,15564.66);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,7 ,1 ,21 ,15644.65);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,8 ,1 ,21 ,16434.82);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,9 ,1 ,21 ,19654.57);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,10 ,1 ,21 ,21764.19);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,11 ,1 ,21 ,13026.73);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2006,12 ,2 ,21 ,10034.64);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,1 ,2 ,22 ,16634.84);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,1 ,2 ,21 ,26034.84);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,2 ,1 ,21 ,12644.65);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,3 ,1 ,21 ,NULL);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,4 ,1 ,21 ,25026.45);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,5 ,1 ,21 ,17212.66);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,6 ,1 ,21 ,15564.26);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,7 ,2 ,21 ,62654.82);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,8 ,2 ,21 ,26434.82);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,9 ,2 ,21 ,15644.65);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,10 ,2 ,21 ,21264.19);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,11 ,1 ,21 ,13026.73);
1 row created. SQL> insert into all_sales (YEAR,MONTH,PRD_TYPE_ID,EMP_ID,AMOUNT)
2 values(2005,12 ,1 ,21 ,10032.64);
1 row created. SQL> SQL> select * from all_sales;
YEAR MONTH PRD_TYPE_ID EMP_ID AMOUNT
---------- ----------- ---------- ----------
2006 1 1 21 16034.84
2006 2 1 21 15644.65
2006 3 2 21 20167.83
2006 4 2 21 25056.45
2006 5 2 21
2006 6 1 21 15564.66
2006 7 1 21 15644.65
2006 8 1 21 16434.82
2006 9 1 21 19654.57
2006 10 1 21 21764.19
2006 11 1 21 13026.73
2006 12 2 21 10034.64
2005 1 2 22 16634.84
2005 1 2 21 26034.84
2005 2 1 21 12644.65
2005 3 1 21
2005 4 1 21 25026.45
2005 5 1 21 17212.66
2005 6 1 21 15564.26
2005 7 2 21 62654.82
2005 8 2 21 26434.82
2005 9 2 21 15644.65
2005 10 2 21 21264.19
2005 11 1 21 13026.73
2005 12 1 21 10032.64
25 rows selected. SQL> SQL> SQL> --Control whether nulls are the highest or lowest in a group using NULLS FIRST SQL> SQL> SELECT
2 prd_type_id, SUM(amount), 3 RANK() OVER (ORDER BY SUM(amount) DESC NULLS FIRST) AS rank, 4 DENSE_RANK() OVER (ORDER BY SUM(amount) DESC NULLS FIRST) AS 5 dense_rank 6 FROM all_sales 7 GROUP BY prd_type_id 8 ORDER BY prd_type_id;
PRD_TYPE_ID SUM(AMOUNT) RANK DENSE_RANK
----------- ---------- ----------
1 227276.5 1 1
2 223927.08 2 2
SQL> SQL> drop table all_sales; Table dropped. SQL> SQL>
</source>
NULLS FIRST: place null value first
<source lang="sql">
SQL> SQL> -- create demo table SQL> create table Employee(
2 empno Number(3) NOT NULL, -- Employee ID 3 ename VARCHAR2(10 BYTE), -- Employee Name 4 hireDate DATE, -- Date Employee Hired 5 orig_salary Number(8,2), -- Orignal Salary 6 curr_salary Number(8,2), -- Current Salary 7 region VARCHAR2(1 BYTE) -- Region where employeed 8 ) 9 /
Table created. SQL> SQL> SQL> -- prepare data for employee table SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(122,"Alison",to_date("19960321","YYYYMMDD"), 45000, NULL, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(123, "James",to_date("19781212","YYYYMMDD"), 23000, 32000, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(104,"Celia",to_date("19821024","YYYYMMDD"), NULL, 58000, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(105,"Robert",to_date("19840115","YYYYMMDD"), 31000, NULL, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(116,"Linda", to_date("19870730","YYYYMMDD"), NULL, 53000, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(117,"David", to_date("19901231","YYYYMMDD"), 78000, NULL, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(108,"Jode", to_date("19960917","YYYYMMDD"), 21000, 29000, "E")
3 /
1 row created. SQL> SQL> -- display data in the table SQL> select * from Employee
2 /
Hit a key to continue
EMPNO ENAME HIREDATE ORIG_SALARY CURR_SALARY R
---------- --------- ----------- ----------- -
122 Alison 21-MAR-96 45000 E
123 James 12-DEC-78 23000 32000 W
104 Celia 24-OCT-82 58000 E
105 Robert 15-JAN-84 31000 W
116 Linda 30-JUL-87 53000 E
117 David 31-DEC-90 78000 W
108 Jode 17-SEP-96 21000 29000 E
7 rows selected. SQL> SQL> SQL> SQL> SQL> SELECT empno, ename, curr_salary,
2 ROW_NUMBER() OVER(ORDER BY curr_salary NULLS FIRST) 3 salary 4 FROM employee 5 ORDER BY curr_salary;
Hit a key to continue
EMPNO ENAME CURR_SALARY SALARY
---------- ----------- ----------
108 Jode 29000 4
123 James 32000 5
116 Linda 53000 6
104 Celia 58000 7
105 Robert 2
117 David 3
122 Alison 1
7 rows selected. SQL> SQL> SQL> SQL> -- clean the table SQL> drop table Employee; Table dropped. SQL> SQL>
</source>
The default is NULLS FIRST
<source lang="sql">
SQL> SQL> -- create demo table SQL> create table Employee(
2 empno Number(3) NOT NULL, -- Employee ID 3 ename VARCHAR2(10 BYTE), -- Employee Name 4 hireDate DATE, -- Date Employee Hired 5 orig_salary Number(8,2), -- Orignal Salary 6 curr_salary Number(8,2), -- Current Salary 7 region VARCHAR2(1 BYTE) -- Region where employeed 8 ) 9 /
Table created. SQL> SQL> SQL> -- prepare data for employee table SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(122,"Alison",to_date("19960321","YYYYMMDD"), 45000, NULL, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(123, "James",to_date("19781212","YYYYMMDD"), 23000, 32000, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(104,"Celia",to_date("19821024","YYYYMMDD"), NULL, 58000, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(105,"Robert",to_date("19840115","YYYYMMDD"), 31000, NULL, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(116,"Linda", to_date("19870730","YYYYMMDD"), NULL, 53000, "E")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(117,"David", to_date("19901231","YYYYMMDD"), 78000, NULL, "W")
3 /
1 row created. SQL> insert into Employee(empno, ename, hireDate, orig_salary, curr_salary, region)
2 values(108,"Jode", to_date("19960917","YYYYMMDD"), 21000, 29000, "E")
3 /
1 row created. SQL> SQL> -- display data in the table SQL> select * from Employee
2 /
Hit a key to continue
EMPNO ENAME HIREDATE ORIG_SALARY CURR_SALARY R
---------- --------- ----------- ----------- -
122 Alison 21-MAR-96 45000 E
123 James 12-DEC-78 23000 32000 W
104 Celia 24-OCT-82 58000 E
105 Robert 15-JAN-84 31000 W
116 Linda 30-JUL-87 53000 E
117 David 31-DEC-90 78000 W
108 Jode 17-SEP-96 21000 29000 E
7 rows selected. SQL> SQL> SQL> SQL> -- The default is NULLS FIRST. To see nulls last in the sort order, the modifier NULLS LAST is used like this: SQL> SQL> SELECT empno, ename, curr_salary,
2 ROW_NUMBER() OVER(ORDER BY curr_salary desc NULLS LAST) 3 salary 4 FROM employee 5 ORDER BY curr_salary desc NULLS LAST;
Hit a key to continue
EMPNO ENAME CURR_SALARY SALARY
---------- ----------- ----------
104 Celia 58000 1
116 Linda 53000 2
123 James 32000 3
108 Jode 29000 4
117 David 5
122 Alison 6
105 Robert 7
7 rows selected. SQL> SQL> SQL> SQL> -- clean the table SQL> drop table Employee; Table dropped. SQL> SQL>
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