day1 session2

7/27/2019 day1 session2
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Entry Level Technology Program
Satyam Learning Center ORACLE 1 of 1
FUNCTIONS

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SQL Functions
FunctionInput
arg 1
arg 2
arg n
Functionperforms action
Output
Resultvalue

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Two Types of SQL Functions
Functions
Single-row
functions
Multiple-row
functions

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Aggregating DataUsing Group Functions

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What Are Group Functions?
Group functions operate on sets of rows togive one result per group.EMPLOYEES
The maximumsalary inthe EMPLOYEES
table.

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Types of Group Functions
AVG
COUNT
MAX
MIN
SUM

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SELECT [column,] group_function(column), ...FROM table
[WHERE condition][GROUP BY column][ORDER BY column];
Group Functions Syntax

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SELECT AVG(SAL), MAX(SAL),
MIN(SAL), SUM(SAL)
FROM EMP
WHERE JOB LIKE '%MAN%';
Using theAVG and SUM
Functions
You can use AVG and SUM for numeric data.

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Using theMIN ,MAX and Count
Functions
You can use MIN and MAX for any data type.
SELECT MIN(HIREDATE), MAX(HIREDATE)
FROM employees;
COUNT(*) returns the number of rows in a table.
SELECT COUNT(*)
FROM EMP
WHERE DEPTNO = 10;

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SELECT COUNT(DISTINCT DEPTNO)
FROM EMP;
Using the DISTINCT Keyword
COUNT(DISTINCT expr) returns the
number of distinct non-null values ofthe expr.
Display the number of distinctdepartment values in the EMPLOYEES
table.

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SELECT AVG(COMM)
FROM EMP;
Group Functions and NullValues
Group functions ignore null values in the column.
The NVL function forces group functions to include
null values.
SELECT AVG(NVL(COMM, 0))
FROM EMP;

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Single-Row Functions
Single row functions: Manipulate data items
Accept arguments and return one value
Act on each row returned
Return one result per row
May modify the data type
Can be nested
Accept arguments which can be a column or anexpression
function_name [(arg1, arg2,...)]

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Single-Row Functions
Conversion
Character
Number
Date
General Single-rowfunctions

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Character Functions
Characterfunctions
LOWER
UPPER
INITCAP
CONCAT
SUBSTR
LENGTH
INSTRLPAD | RPAD
TRIM
REPLACE
Case-manipulationfunctions
Character-manipulationfunctions

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Function Result
Case Manipulation Functions
These functions convert case for character strings.
LOWER('SQL Course')
UPPER('SQL Course')
INITCAP('SQL Course')
sql course
SQL COURSE
Sql Course

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Using Case ManipulationFunctions
Display the employee number, name, and departmentnumber for employee Higgins:
SELECT EMPNO, ENAME, DEPTNOFROM EMPWHERE ENAME = smith';no rows selected
SELECT EMPNO, ENAME, DEPTNO
FROM EMPWHERE LOWER(ENAME) = smith';

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CONCAT('Hello', 'World')SUBSTR('HelloWorld',1,5)
LENGTH('HelloWorld')
INSTR('HelloWorld', 'W')
LPAD(salary,10,'*')RPAD(salary, 10, '*')
TRIM('H' FROM 'HelloWorld')
HelloWorldHello
10
6
*****2400024000*****
elloWorld
Function Result
Character-Manipulation Functions
These functions manipulate character strings:

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SELECT EMPNO, CONCAT(ENAME,JOB) NAME,
JOB, LENGTH (ENAME),
INSTR(ENAME, 'a') "Contains 'a'?"
FROM EMP
WHERE SUBSTR(JOB, 6) = MAN';
Using the Character-Manipulation Functions

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Number Functions
ROUND: Rounds value to specified decimal
ROUND(45.926, 2) 45.93
TRUNC: Truncates value to specified decimal
TRUNC(45.926, 2) 45.92
MOD
: Returns remainder of division
MOD(1600, 300) 100

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SELECT ROUND(45.923,2), ROUND(45.923,0),
ROUND(45.923,-1)
FROM DUAL;
Using the ROUND Function
DUAL is a dummy table you can use to view resultsfrom functions and calculations.

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SELECT TRUNC(45.923,2), TRUNC(45.923),
TRUNC(45.923,-2)
FROM DUAL;
Using the TRUNC Function

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SELECT ENAME, SAL, MOD(SAL, 5000)
FROM EMP
WHERE JOB = 'SALESMAN';
Using theMOD Function
Calculate the remainder of a salary after it is divided by 5000for all employees whose job title is sales representative.

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Working with Dates
Oracle database stores dates in an internal numeric format:century, year, month, day, hours, minutes, seconds.
The default date display format is DD-MON-RR.
Allows you to store 21st century dates in the 20thcentury by specifying only the last two digits of the year.
Allows you to store 20th century dates in the 21stcentury in the same way.
SELECT ENAME, HIREDATE
FROM EMP
WHERE ENAME like 'G%';
0

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Working with Dates
SYSDATEis a function that returns:
Date
Time

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Arithmetic with Dates
Add or subtract a number to or from a date for a
resultant date value. Subtract two dates to find the number of days
between those dates.
Add hours to a date by dividing the number of
hours by 24.

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Using Arithmetic Operatorswith Dates
SELECT ENAME, (SYSDATE-HIREDATE)/7 AS WEEKS
FROM EMP
WHERE DEPTNO = 20;

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Date Functions
Number of monthsbetween two dates
MONTHS_BETWEEN
ADD_MONTHS
NEXT_DAY
LAST_DAY
ROUND
TRUNC
Add calendar months todate
Next day of the datespecified
Last day of the month
Round date
Truncate date
Function Description

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MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')
Using Date Functions
ADD_MONTHS ('11-JAN-94',6)
NEXT_DAY ('01-SEP-95','FRIDAY')
LAST_DAY('01-FEB-95')
19.6774194
'11-JUL-94'
'08-SEP-95'
'28-FEB-95'

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ROUND(SYSDATE,'MONTH') 01-AUG-95
ROUND(SYSDATE ,'YEAR') 01-JAN-96
TRUNC(SYSDATE ,'MONTH') 01-JUL-95
TRUNC(SYSDATE ,'YEAR') 01-JAN-95
Using Date Functions
Assume SYSDATE = '25-JUL-95':

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Entry Leve

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