FIRST_VALUE and LAST_VALUE Analytic Functions
Simple examples of how to use the FIRST_VALUE and LAST_VALUE analytic functions.
oracle miscconfigurationintermediate
by OracleDba
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📋Steps in this guide1/4
1
Setup
The examples in this article require the following table.
Code/Command (click line numbers to comment):
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--DROP TABLE emp PURGE;
CREATE TABLE emp (
empno NUMBER(4) CONSTRAINT pk_emp PRIMARY KEY,
ename VARCHAR2(10),
job VARCHAR2(9),
mgr NUMBER(4),
hiredate DATE,
sal NUMBER(7,2),
comm NUMBER(7,2),
deptno NUMBER(2)
);
INSERT INTO emp VALUES (7369,'SMITH','CLERK',7902,to_date('17-12-1980','dd-mm-yyyy'),800,NULL,20);
INSERT INTO emp VALUES (7499,'ALLEN','SALESMAN',7698,to_date('20-2-1981','dd-mm-yyyy'),1600,300,30);
INSERT INTO emp VALUES (7521,'WARD','SALESMAN',7698,to_date('22-2-1981','dd-mm-yyyy'),1250,500,30);
INSERT INTO emp VALUES (7566,'JONES','MANAGER',7839,to_date('2-4-1981','dd-mm-yyyy'),2975,NULL,20);
INSERT INTO emp VALUES (7654,'MARTIN','SALESMAN',7698,to_date('28-9-1981','dd-mm-yyyy'),1250,1400,30);
INSERT INTO emp VALUES (7698,'BLAKE','MANAGER',7839,to_date('1-5-1981','dd-mm-yyyy'),2850,NULL,30);
INSERT INTO emp VALUES (7782,'CLARK','MANAGER',7839,to_date('9-6-1981','dd-mm-yyyy'),2450,NULL,10);
INSERT INTO emp VALUES (7788,'SCOTT','ANALYST',7566,to_date('13-JUL-87','dd-mm-rr')-85,3000,NULL,20);
INSERT INTO emp VALUES (7839,'KING','PRESIDENT',NULL,to_date('17-11-1981','dd-mm-yyyy'),5000,NULL,10);
INSERT INTO emp VALUES (7844,'TURNER','SALESMAN',7698,to_date('8-9-1981','dd-mm-yyyy'),1500,0,30);
INSERT INTO emp VALUES (7876,'ADAMS','CLERK',7788,to_date('13-JUL-87', 'dd-mm-rr')-51,1100,NULL,20);
INSERT INTO emp VALUES (7900,'JAMES','CLERK',7698,to_date('3-12-1981','dd-mm-yyyy'),950,NULL,30);
INSERT INTO emp VALUES (7902,'FORD','ANALYST',7566,to_date('3-12-1981','dd-mm-yyyy'),3000,NULL,20);
INSERT INTO emp VALUES (7934,'MILLER','CLERK',7782,to_date('23-1-1982','dd-mm-yyyy'),1300,NULL,10);
COMMIT;2
FIRST_VALUE
The basic description for the analytic function is shown below. The analytic clause is described in more detail here .
The analytic function is similar to the analytic function, allowing you to return the first result from an ordered set.
The " " clause indicates if NULLs are considered when determining results.
The windowing clause can be used to alter the window of operation. The following example uses " " to give a result similar, but not quite the same, to a of 1 row.
Code/Command (click line numbers to comment):
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FIRST_VALUE
{ (expr) [ {RESPECT | IGNORE} NULLS ]
| (expr [ {RESPECT | IGNORE} NULLS ])
}
OVER (analytic_clause)
SELECT empno,
deptno,
sal,
FIRST_VALUE(sal) IGNORE NULLS
OVER (PARTITION BY deptno ORDER BY sal) AS lowest_in_dept
FROM emp;
EMPNO DEPTNO SAL LOWEST_IN_DEPT
---------- ---------- ---------- --------------
7934 10 1300 1300
7782 10 2450 1300
7839 10 5000 1300
7369 20 800 800
7876 20 1100 800
7566 20 2975 800
7788 20 3000 800
7902 20 3000 800
7900 30 950 950
7654 30 1250 950
7521 30 1250 950
7844 30 1500 950
7499 30 1600 950
7698 30 2850 950
SQL>
SELECT empno,
deptno,
sal,
FIRST_VALUE(sal) IGNORE NULLS
OVER (PARTITION BY deptno ORDER BY sal ROWS 1 PRECEDING) AS preceding_in_dept
FROM emp;
EMPNO DEPTNO SAL PRECEDING_IN_DEPT
---------- ---------- ---------- -----------------
7934 10 1300 1300
7782 10 2450 1300
7839 10 5000 2450
7369 20 800 800
7876 20 1100 800
7566 20 2975 1100
7788 20 3000 2975
7902 20 3000 3000
7900 30 950 950
7654 30 1250 950
7521 30 1250 1250
7844 30 1500 1250
7499 30 1600 1500
7698 30 2850 1600
SQL>3
LAST_VALUE
The basic description for the analytic function is shown below. The analytic clause is described in more detail here .
The analytic function is similar to the analytic function, allowing you to return the last result from an ordered set. Using the default windowing clause the result can be a little unexpected.
This is because the default windowing clause is " ", which in this example means the first row with the same value as that of the current row will always be the last row considered. Altering the windowing clause to " " gives us the result we probably expected.
As with the previous function, the " " clause indicates if NULLs are considered when determining results. The default action is .
Code/Command (click line numbers to comment):
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657
LAST_VALUE
{ (expr) [ { RESPECT | IGNORE } NULLS ]
| (expr [ { RESPECT | IGNORE } NULLS ])
OVER (analytic_clause)
SELECT empno,
deptno,
sal,
LAST_VALUE(sal) IGNORE NULLS
OVER (PARTITION BY deptno ORDER BY sal) AS highest_in_dept
FROM emp;
EMPNO DEPTNO SAL HIGHEST_IN_DEPT
---------- ---------- ---------- ---------------
7934 10 1300 1300
7782 10 2450 2450
7839 10 5000 5000
7369 20 800 800
7876 20 1100 1100
7566 20 2975 2975
7788 20 3000 3000
7902 20 3000 3000
7900 30 950 950
7654 30 1250 1250
7521 30 1250 1250
7844 30 1500 1500
7499 30 1600 1600
7698 30 2850 2850
SQL>
SELECT empno,
deptno,
sal,
LAST_VALUE(sal) IGNORE NULLS
OVER (PARTITION BY deptno ORDER BY sal ROWS BETWEEN
UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS highest_in_dept
FROM emp;
EMPNO DEPTNO SAL HIGHEST_IN_DEPT
---------- ---------- ---------- ---------------
7934 10 1300 5000
7782 10 2450 5000
7839 10 5000 5000
7369 20 800 3000
7876 20 1100 3000
7566 20 2975 3000
7788 20 3000 3000
7902 20 3000 3000
7900 30 950 2850
7654 30 1250 2850
7521 30 1250 2850
7844 30 1500 2850
7499 30 1600 2850
7698 30 2850 2850
SQL>4
Quick Links
The "*" indicates the function supports the full analytic syntax, including the windowing clause.
For more information see:
- FIRST_VALUE and LAST_VALUE Analytic Functions
- Analytic Functions : All Articles
- Analytic Functions
- Top-N Queries
- FIRST_VALUE
- LAST_VALUE
Hope this helps. Regards Tim...
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