Single-row functions

Август 1, 2022

Содержание

2. Objectives After completing this lesson, you should be able to do the following: Describe various types
3. SQL Functions Function Function performs action
4. Two Types of SQL Functions Functions Single-row functions Multiple-row functions
5. Single-Row Functions Manipulate data items Accept arguments and return one value Act on each row returned
6. Single-Row Functions Conversion Character Number Date General Single-row functions
7. Character Functions Character functions LOWER UPPER INITCAP CONCAT SUBSTR LENGTH INSTR LPAD Case conversion functions Character
8. Function Result Case Conversion Functions Convert case for character strings LOWER('SQL Course') UPPER('SQL Course') INITCAP('SQL Course')
9. Using Case Conversion Functions Display the employee number, name, and department number for employee Blake. SQL>
10. CONCAT('Good', 'String') SUBSTR('String',1,3) LENGTH('String') INSTR('String', 'r') LPAD(sal,10,'*') GoodString Str 6 3 ******5000 Function Result Character Manipulation
11. Using the Character Manipulation Functions SQL> SELECT ename, CONCAT (ename, job), LENGTH(ename), 2 INSTR(ename, 'A') 3
12. Number Functions ROUND: Rounds value to specified decimal ROUND(45.926, 2) 45.93 TRUNC: Truncates value to specified
13. Using the ROUND Function SQL> SELECT ROUND(45.923,2), ROUND(45.923,0), 2 ROUND(45.923,-1) 3 FROM DUAL; ROUND(45.923,2) ROUND(45.923,0) ROUND(45.923,-1)
14. SQL> SELECT TRUNC(45.923,2), TRUNC(45.923), 2 TRUNC(45.923,-1) 3 FROM DUAL; TRUNC(45.923,2) TRUNC(45.923) TRUNC(45.923,-1) --------------- ------------- --------------- 45.92
15. Using the MOD Function Calculate the remainder of the ratio of salary to commission for all
16. Working with Dates Oracle stores dates in an internal numeric format: Century, year, month, day, hours,
17. Arithmetic with Dates Add or subtract a number to or from a date for a resultant
18. Using Arithmetic Operators with Dates SQL> SELECT ename, (SYSDATE-hiredate)/7 WEEKS 2 FROM emp 3 WHERE deptno
19. Date Functions Number of months between two dates MONTHS_BETWEEN ADD_MONTHS NEXT_DAY LAST_DAY ROUND TRUNC Add calendar
20. 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-SEP-95') 19.6774194 '11-JUL-94' '08-SEP-95' '30-SEP-95'
21. Using Date Functions
22. Conversion Functions Implicit datatype conversion Explicit datatype conversion Datatype conversion
23. Implicit Datatype Conversion For assignments, Oracle can automatically convert VARCHAR2 or CHAR From To VARCHAR2 or
24. Implicit Datatype Conversion For expression evaluation, Oracle can automatically convert VARCHAR2 or CHAR From To VARCHAR2
25. Explicit Datatype Conversion NUMBER CHARACTER TO_CHAR
26. TO_CHAR Function with Dates The format model: Must be enclosed in single quotation marks and is
27. YYYY Date Format Model Elements YEAR MM MONTH DY DAY Full year in numbers Year spelled
28. Date Format Model Elements Time elements format the time portion of the date. Add character strings
29. Using TO_CHAR Function with Dates SQL> SELECT ename, 2 TO_CHAR(hiredate, 'fmDD Month YYYY') HIREDATE 3 FROM
30. TO_CHAR Function with Numbers Use these formats with the TO_CHAR function to display a number value
31. Using TO_CHAR Function with Numbers SQL> SELECT TO_CHAR(sal,'$99,999') SALARY 2 FROM emp 3 WHERE ename =
32. TO_NUMBER and TO_DATE Functions Convert a character string to a number format using the TO_NUMBER function
33. RR Date Format Current Year 1995 1995 2001 2001 Specified Date 27-OCT-95 27-OCT-17 27-OCT-17 27-OCT-95 RR
34. NVL Function Converts null to an actual value Datatypes that can be used are date, character,
35. SQL> SELECT ename, sal, comm, (sal*12)+NVL(comm,0) 2 FROM emp; Using the NVL Function ENAME SAL COMM
36. DECODE Function Facilitates conditional inquiries by doing the work of a CASE or IF-THEN-ELSE statement DECODE(col/expression,
37. Using the DECODE Function SQL> SELECT job, sal, 2 DECODE(job, 'ANALYST', SAL*1.1, 3 'CLERK', SAL*1.15, 4
38. Nesting Functions Single-row functions can be nested to any level. Nested functions are evaluated from deepest
39. Nesting Functions SQL> SELECT ename, 2 NVL(TO_CHAR(mgr),'No Manager') 3 FROM emp 4 WHERE mgr IS NULL;
40. Summary Use functions to: Perform calculations on data Modify individual data items Manipulate output for groups
41. Practice Overview Creating queries that require the use of numeric, character, and date functions Using concatenation
47. Скачать презентацию

Слайд 2

Objectives
After completing this lesson, you should be able to do the

following:
Describe various types of functions available in SQL
Use character, number, and date functions in SELECT statements
Describe the use of conversion functions

Слайд 3

SQL Functions
Function
Function performs action

Слайд 4

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

Слайд 5

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 datatype
Can be nested

function_name (column|expression, [arg1, arg2,...])

Слайд 6

Single-Row Functions
Conversion
Character
Number
Date
General
Single-row
functions

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Character Functions
Character
functions
LOWER
UPPER
INITCAP
CONCAT
SUBSTR
LENGTH
INSTR
LPAD
Case conversion
functions
Character manipulation
functions

Слайд 8

Function
Result
Case Conversion Functions
Convert case for character strings
LOWER('SQL Course')
UPPER('SQL Course')
INITCAP('SQL Course')
sql course
SQL

COURSE
Sql Course

Слайд 9

Using Case Conversion Functions
Display the employee number, name, and department number

for employee Blake.

SQL> SELECT empno, ename, deptno
2 FROM emp
3 WHERE ename = 'blake';
no rows selected

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CONCAT('Good', 'String')
SUBSTR('String',1,3)
LENGTH('String')
INSTR('String', 'r')
LPAD(sal,10,'*')
GoodString
Str
6
3
******5000
Function
Result
Character Manipulation Functions
Manipulate character strings

Слайд 11

Using the Character Manipulation Functions
SQL> SELECT ename, CONCAT (ename, job), LENGTH(ename),

2 INSTR(ename, 'A')
3 FROM emp
4 WHERE

SUBSTR(job,1,5) = 'SALES';

ENAME CONCAT(ENAME,JOB) LENGTH(ENAME) INSTR(ENAME,'A')
---------- ------------------- ------------- ----------------
MARTIN MARTINSALESMAN 6 2
ALLEN ALLENSALESMAN 5 1
TURNER TURNERSALESMAN 6 0
WARD WARDSALESMAN 4 2

Слайд 12

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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Using the ROUND Function
SQL> SELECT ROUND(45.923,2), ROUND(45.923,0),
2 ROUND(45.923,-1)
3 FROM

DUAL;

ROUND(45.923,2) ROUND(45.923,0) ROUND(45.923,-1)
--------------- -------------- -----------------
45.92 46 50

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SQL> SELECT TRUNC(45.923,2), TRUNC(45.923),
2 TRUNC(45.923,-1)
3 FROM DUAL;
TRUNC(45.923,2) TRUNC(45.923) TRUNC(45.923,-1)
---------------

------------- ---------------
45.92 45 40

Using the TRUNC Function

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Using the MOD Function
Calculate the remainder of the ratio of salary

to commission for all employees whose job title is a salesman.

SQL> SELECT ename, sal, comm, MOD(sal, comm)
2 FROM emp
3 WHERE job = 'SALESMAN';

ENAME SAL COMM MOD(SAL,COMM)
---------- --------- --------- -------------
MARTIN 1250 1400 1250
ALLEN 1600 300 100
TURNER 1500 0 1500
WARD 1250 500 250

Слайд 16

Working with Dates
Oracle stores dates in an internal numeric format: Century,

year, month, day, hours, minutes, seconds.
The default date format is DD-MON-YY.
SYSDATE is a function returning date and time.
DUAL is a dummy table used to view SYSDATE.

Слайд 17

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 Operators with Dates
SQL> SELECT ename, (SYSDATE-hiredate)/7 WEEKS
2 FROM emp

3 WHERE deptno = 10;

ENAME WEEKS
---------- ---------
KING 830.93709
CLARK 853.93709
MILLER 821.36566

Слайд 19

Date Functions
Number of months between two dates
MONTHS_BETWEEN
ADD_MONTHS
NEXT_DAY
LAST_DAY
ROUND
TRUNC
Add calendar months to date
Next

day of the date specified

Last day of the month

Round date

Truncate date

FUNCTION

DESCRIPTION

Слайд 20

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-SEP-95')
19.6774194
'11-JUL-94'
'08-SEP-95'
'30-SEP-95'

Слайд 21

Using Date Functions

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Conversion Functions
Implicit datatype
conversion
Explicit datatype
conversion
Datatype
conversion

Слайд 23

Implicit Datatype Conversion
For assignments, Oracle can automatically convert
VARCHAR2 or CHAR
From
To
VARCHAR2 or

CHAR

NUMBER

DATE

NUMBER

DATE

VARCHAR2

Слайд 24

Implicit Datatype Conversion
For expression evaluation, Oracle can automatically convert
VARCHAR2 or CHAR
From
To
VARCHAR2

or CHAR

NUMBER

DATE

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Explicit Datatype Conversion
NUMBER
CHARACTER
TO_CHAR

Слайд 26

TO_CHAR Function with Dates
The format model:
Must be enclosed in single quotation

marks and is case sensitive
Can include any valid date format element
Has an fm element to remove padded blanks or suppress leading zeros
Is separated from the date value by a comma

TO_CHAR(date, 'fmt')

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YYYY
Date Format Model Elements
YEAR
MM
MONTH
DY
DAY
Full year in numbers
Year spelled out
2-digit value for

month

3-letter abbreviation of the day of the week

Full name of the day

Full name of the month

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Date Format Model Elements
Time elements format the time portion of the

date.
Add character strings by enclosing them in double quotation marks.
Number suffixes spell out numbers.

HH24:MI:SS AM

15:45:32 PM

DD "of" MONTH

12 of OCTOBER

ddspth

fourteenth

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Using TO_CHAR Function with Dates
SQL> SELECT ename,
2 TO_CHAR(hiredate, 'fmDD Month

YYYY') HIREDATE
3 FROM emp;

ENAME HIREDATE
---------- -----------------
KING 17 November 1981
BLAKE 1 May 1981
CLARK 9 June 1981
JONES 2 April 1981
MARTIN 28 September 1981
ALLEN 20 February 1981
...
14 rows selected.

Слайд 30

TO_CHAR Function with Numbers
Use these formats with the TO_CHAR function to

display a number value as a character.

TO_CHAR(number, 'fmt')

Represents a number

Forces a zero to be displayed

Places a floating dollar sign

Uses the floating local currency symbol

Prints a decimal point

Prints a thousand indicator

Слайд 31

Using TO_CHAR Function with Numbers
SQL> SELECT TO_CHAR(sal,'$99,999') SALARY
2 FROM emp
3 WHERE ename

= 'SCOTT';

SALARY
--------
$3,000

Слайд 32

TO_NUMBER and TO_DATE Functions
Convert a character string to a number

format using the TO_NUMBER function

TO_NUMBER(char)

Convert a character string to a date format using the TO_DATE function

TO_DATE(char[, 'fmt'])

Слайд 33

RR Date Format
Current Year
1995
1995
2001
2001
Specified Date
27-OCT-95
27-OCT-17
27-OCT-17
27-OCT-95
RR Format
1995
2017
2017
1995
YY Format
1995
1917
2017
2095
If two digits of the

current year are

0-49

50-99

The return date is in the current century.

The return date is in the century after the current one.

The return date is in the century before the current one.

The return date is in the current century.

If the specified two-digit year is

Слайд 34

NVL Function
Converts null to an actual value
Datatypes that can be used

are date, character, and number.
Datatypes must match
NVL(comm,0)
NVL(hiredate,'01-JAN-97')
NVL(job,'No Job Yet')

Слайд 35

SQL> SELECT ename, sal, comm, (sal*12)+NVL(comm,0)
2 FROM emp;
Using the NVL

Function

ENAME SAL COMM (SAL*12)+NVL(COMM,0)
---------- --------- --------- --------------------
KING 5000 60000
BLAKE 2850 34200
CLARK 2450 29400
JONES 2975 35700
MARTIN 1250 1400 16400
ALLEN 1600 300 19500
...
14 rows selected.

Слайд 36

DECODE Function
Facilitates conditional inquiries by doing the work of a CASE

or IF-THEN-ELSE statement

DECODE(col/expression, search1, result1
[, search2, result2,...,]
[, default])

Слайд 37

Using the DECODE Function
SQL> SELECT job, sal,
2 DECODE(job, 'ANALYST', SAL*1.1,

3 'CLERK', SAL*1.15,
4 'MANAGER', SAL*1.20,
5 SAL)
6 REVISED_SALARY
7 FROM emp;

JOB SAL REVISED_SALARY
--------- --------- --------------
PRESIDENT 5000 5000
MANAGER 2850 3420
MANAGER 2450 2940
...
14 rows selected.

Слайд 38

Nesting Functions
Single-row functions can be nested to any level.
Nested functions are

evaluated from deepest level to the least deep level.

F3(F2(F1(col,arg1),arg2),arg3)

Step 1 = Result 1

Step 2 = Result 2

Step 3 = Result 3

Слайд 39

Nesting Functions
SQL> SELECT ename,
2 NVL(TO_CHAR(mgr),'No Manager')
3 FROM emp
4 WHERE mgr IS

NULL;

ENAME NVL(TO_CHAR(MGR),'NOMANAGER')
---------- -----------------------------
KING No Manager

Слайд 40

Summary
Use functions to:
Perform calculations on data
Modify individual data items
Manipulate output for

groups of rows
Alter date formats for display
Convert column datatypes

Слайд 41

Practice Overview
Creating queries that require the use of numeric, character, and

date functions
Using concatenation with functions
Writing case-insensitive queries to test the usefulness of character functions
Performing calculations of years and months of service for an employee
Determining the review date for an employee

Слайд 42

Слайд 43

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Слайд 45

Single-row functions

Содержание

ObjectivesAfter completing this lesson, you should be able to do the

SQL FunctionsFunctionFunction performs action

Two Types of SQL FunctionsFunctionsSingle-row functionsMultiple-rowfunctions

Single-Row FunctionsManipulate data itemsAccept arguments and return one valueAct on each

Single-Row FunctionsConversionCharacterNumberDateGeneralSingle-row functions

Character FunctionsCharacterfunctionsLOWERUPPERINITCAPCONCATSUBSTRLENGTHINSTRLPADCase conversion functionsCharacter manipulationfunctions

FunctionResultCase Conversion FunctionsConvert case for character stringsLOWER('SQL Course')UPPER('SQL Course')INITCAP('SQL Course')sql courseSQL

Using Case Conversion FunctionsDisplay the employee number, name, and department number

CONCAT('Good', 'String')SUBSTR('String',1,3)LENGTH('String')INSTR('String', 'r')LPAD(sal,10,'*')GoodStringStr63******5000FunctionResultCharacter Manipulation FunctionsManipulate character strings

Using the Character Manipulation FunctionsSQL> SELECT ename, CONCAT (ename, job), LENGTH(ename),

Number FunctionsROUND: Rounds value to specified decimalROUND(45.926, 2) 45.93TRUNC: Truncates value to specified decimalTRUNC(45.926, 2)

Using the ROUND FunctionSQL> SELECT ROUND(45.923,2), ROUND(45.923,0), 2 ROUND(45.923,-1) 3 FROM

SQL> SELECT TRUNC(45.923,2), TRUNC(45.923), 2 TRUNC(45.923,-1) 3 FROM DUAL;TRUNC(45.923,2) TRUNC(45.923) TRUNC(45.923,-1)---------------

Using the MOD FunctionCalculate the remainder of the ratio of salary

Working with DatesOracle stores dates in an internal numeric format: Century,

Arithmetic with DatesAdd or subtract a number to or from a

Using Arithmetic Operators with DatesSQL> SELECT ename, (SYSDATE-hiredate)/7 WEEKS 2 FROM emp

Date FunctionsNumber of months between two datesMONTHS_BETWEENADD_MONTHSNEXT_DAY LAST_DAYROUND TRUNC Add calendar months to dateNext

MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')Using Date FunctionsADD_MONTHS ('11-JAN-94',6)NEXT_DAY ('01-SEP-95','FRIDAY') LAST_DAY('01-SEP-95')19.6774194'11-JUL-94''08-SEP-95''30-SEP-95'

Using Date Functions

Conversion FunctionsImplicit datatypeconversionExplicit datatypeconversionDatatypeconversion

Implicit Datatype ConversionFor assignments, Oracle can automatically convertVARCHAR2 or CHARFromToVARCHAR2 or

Implicit Datatype ConversionFor expression evaluation, Oracle can automatically convertVARCHAR2 or CHARFromToVARCHAR2

Explicit Datatype ConversionNUMBERCHARACTERTO_CHAR

TO_CHAR Function with DatesThe format model:Must be enclosed in single quotation

YYYYDate Format Model ElementsYEARMMMONTHDYDAYFull year in numbersYear spelled out2-digit value for

Date Format Model ElementsTime elements format the time portion of the

Using TO_CHAR Function with DatesSQL> SELECT ename, 2 TO_CHAR(hiredate, 'fmDD Month

TO_CHAR Function with NumbersUse these formats with the TO_CHAR function to

Using TO_CHAR Function with NumbersSQL> SELECT TO_CHAR(sal,'$99,999') SALARY 2 FROM emp 3 WHERE ename

TO_NUMBER and TO_DATE Functions Convert a character string to a number

RR Date FormatCurrent Year1995199520012001Specified Date27-OCT-9527-OCT-1727-OCT-1727-OCT-95RR Format1995201720171995YY Format1995191720172095If two digits of the

NVL FunctionConverts null to an actual valueDatatypes that can be used

SQL> SELECT ename, sal, comm, (sal*12)+NVL(comm,0) 2 FROM emp;Using the NVL

DECODE FunctionFacilitates conditional inquiries by doing the work of a CASE

Using the DECODE FunctionSQL> SELECT job, sal, 2 DECODE(job, 'ANALYST', SAL*1.1,

Nesting FunctionsSingle-row functions can be nested to any level.Nested functions are

Nesting FunctionsSQL> SELECT ename, 2 NVL(TO_CHAR(mgr),'No Manager') 3 FROM emp 4 WHERE mgr IS

SummaryUse functions to:Perform calculations on dataModify individual data itemsManipulate output for

Practice OverviewCreating queries that require the use of numeric, character, and

Похожие презентации

Objectives
After completing this lesson, you should be able to do the

SQL Functions
Function
Function performs action

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

Single-Row Functions
Manipulate data items
Accept arguments and return one value
Act on each

Single-Row Functions
Conversion
Character
Number
Date
General
Single-row
functions

Character Functions
Character
functions
LOWER
UPPER
INITCAP
CONCAT
SUBSTR
LENGTH
INSTR
LPAD
Case conversion
functions
Character manipulation
functions

Function
Result
Case Conversion Functions
Convert case for character strings
LOWER('SQL Course')
UPPER('SQL Course')
INITCAP('SQL Course')
sql course
SQL

Using Case Conversion Functions
Display the employee number, name, and department number

CONCAT('Good', 'String')
SUBSTR('String',1,3)
LENGTH('String')
INSTR('String', 'r')
LPAD(sal,10,'*')
GoodString
Str
6
3
******5000
Function
Result
Character Manipulation Functions
Manipulate character strings

Using the Character Manipulation Functions
SQL> SELECT ename, CONCAT (ename, job), LENGTH(ename),

Number Functions
ROUND: Rounds value to specified decimal
ROUND(45.926, 2) 45.93
TRUNC: Truncates value to specified decimal
TRUNC(45.926, 2)

Using the ROUND Function
SQL> SELECT ROUND(45.923,2), ROUND(45.923,0),
2 ROUND(45.923,-1)
3 FROM

SQL> SELECT TRUNC(45.923,2), TRUNC(45.923),
2 TRUNC(45.923,-1)
3 FROM DUAL;
TRUNC(45.923,2) TRUNC(45.923) TRUNC(45.923,-1)
---------------

Using the MOD Function
Calculate the remainder of the ratio of salary

Working with Dates
Oracle stores dates in an internal numeric format: Century,

Arithmetic with Dates
Add or subtract a number to or from a

Using Arithmetic Operators with Dates
SQL> SELECT ename, (SYSDATE-hiredate)/7 WEEKS
2 FROM emp

Date Functions
Number of months between two dates
MONTHS_BETWEEN
ADD_MONTHS
NEXT_DAY
LAST_DAY
ROUND
TRUNC
Add calendar months to date
Next

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-SEP-95')
19.6774194
'11-JUL-94'
'08-SEP-95'
'30-SEP-95'

Conversion Functions
Implicit datatype
conversion
Explicit datatype
conversion
Datatype
conversion

Implicit Datatype Conversion
For assignments, Oracle can automatically convert
VARCHAR2 or CHAR
From
To
VARCHAR2 or

Implicit Datatype Conversion
For expression evaluation, Oracle can automatically convert
VARCHAR2 or CHAR
From
To
VARCHAR2

Explicit Datatype Conversion
NUMBER
CHARACTER
TO_CHAR

TO_CHAR Function with Dates
The format model:
Must be enclosed in single quotation

YYYY
Date Format Model Elements
YEAR
MM
MONTH
DY
DAY
Full year in numbers
Year spelled out
2-digit value for

Date Format Model Elements
Time elements format the time portion of the

Using TO_CHAR Function with Dates
SQL> SELECT ename,
2 TO_CHAR(hiredate, 'fmDD Month

TO_CHAR Function with Numbers
Use these formats with the TO_CHAR function to

Using TO_CHAR Function with Numbers
SQL> SELECT TO_CHAR(sal,'$99,999') SALARY
2 FROM emp
3 WHERE ename

TO_NUMBER and TO_DATE Functions
Convert a character string to a number

RR Date Format
Current Year
1995
1995
2001
2001
Specified Date
27-OCT-95
27-OCT-17
27-OCT-17
27-OCT-95
RR Format
1995
2017
2017
1995
YY Format
1995
1917
2017
2095
If two digits of the

NVL Function
Converts null to an actual value
Datatypes that can be used

SQL> SELECT ename, sal, comm, (sal*12)+NVL(comm,0)
2 FROM emp;
Using the NVL

DECODE Function
Facilitates conditional inquiries by doing the work of a CASE

Using the DECODE Function
SQL> SELECT job, sal,
2 DECODE(job, 'ANALYST', SAL*1.1,

Nesting Functions
Single-row functions can be nested to any level.
Nested functions are

Nesting Functions
SQL> SELECT ename,
2 NVL(TO_CHAR(mgr),'No Manager')
3 FROM emp
4 WHERE mgr IS

Summary
Use functions to:
Perform calculations on data
Modify individual data items
Manipulate output for

Practice Overview
Creating queries that require the use of numeric, character, and