MAX
Syntax
See Also:
"Analytic Functions" for information on syntax, semantics, and restrictions
Purpose
MAX returns maximum value of expr. You can use it as an aggregate or analytic function.
See Also:
-
"About SQL Expressions" for information on valid forms of
expr, "Floating-Point Numbers" for information on binary-float comparison semantics, and "Aggregate Functions" -
Appendix C in Oracle Database Globalization Support Guide for the collation determination rules, which define the collation
MAXuses to compare character values forexpr, and for the collation derivation rules, which define the collation assigned to the return value of this function when it is a character value
Aggregate Example
The following example determines the highest salary in the hr.employees table:
SELECT MAX(salary) "Maximum"
FROM employees;
Maximum
----------
24000Analytic Examples
The following example calculates, for each employee, the highest salary of the employees reporting to the same manager as the employee.
SELECT manager_id, last_name, salary,
MAX(salary) OVER (PARTITION BY manager_id) AS mgr_max
FROM employees
ORDER BY manager_id, last_name, salary;
MANAGER_ID LAST_NAME SALARY MGR_MAX
---------- ------------------------- ---------- ----------
100 Cambrault 11000 17000
100 De Haan 17000 17000
100 Errazuriz 12000 17000
100 Fripp 8200 17000
100 Hartstein 13000 17000
100 Kaufling 7900 17000
100 Kochhar 17000 17000
. . .
If you enclose this query in the parent query with a predicate, then you can determine the employee who makes the highest salary in each department:
SELECT manager_id, last_name, salary
FROM (SELECT manager_id, last_name, salary,
MAX(salary) OVER (PARTITION BY manager_id) AS rmax_sal
FROM employees)
WHERE salary = rmax_sal
ORDER BY manager_id, last_name, salary;
MANAGER_ID LAST_NAME SALARY
---------- ------------------------- ----------
100 De Haan 17000
100 Kochhar 17000
101 Greenberg 12008
101 Higgins 12008
102 Hunold 9000
103 Ernst 6000
108 Faviet 9000
114 Khoo 3100
120 Nayer 3200
120 Taylor 3200
121 Sarchand 4200
122 Chung 3800
123 Bell 4000
124 Rajs 3500
145 Tucker 10000
146 King 10000
147 Vishney 10500
148 Ozer 11500
149 Abel 11000
201 Fay 6000
205 Gietz 8300
King 24000
22 rows selected.