FUNCTIONS
Functions can be categorized as follows.
- Single row functions
- Group functions
SINGLE ROW FUNCTIONS
Single row functions can be categorized into five.
These will be applied for each row and produces individual output for each row.
- Numeric functions
- String functions
- Date functions
- Miscellaneous functions
- Conversion functions
NUMERIC FUNCTIONS
- Abs
- Sign
- Sqrt
- Mod
- Nvl
- Power
- Exp
- Ln
- Log
- Ceil
- Floor
- Round
- Trunk
- Bitand
- Greatest
- Least
- Coalesce
- ABS :
Absolute value is the measure of the magnitude of value.
Absolute value is always a positive number.
Syntax:
abs (value)
Ex:
SQL> select abs(5), abs(-5), abs(0), abs(null) from dual;
ABS(5) ABS(-5) ABS(0) ABS(NULL)
------ ------- ------ ---------
5 -5 0
- SIGN :
Sign gives the sign of a value.
Syntax:
sign (value)
Ex:
SQL> select sign(5), sign(-5), sign(0), sign(null) from dual;
SIGN(5) SIGN(-5) SIGN(0) SIGN(NULL)
------- -------- ------- ----------
1 -1 0
- SQRT :
This will give the square root of the given value.
Syntax:
sqrt (value) -- here value must be positive.
Ex:
SQL> select sqrt(4), sqrt(0), sqrt(null), sqrt(1) from dual;
SQRT(4) SQRT(0) SQRT(NULL) SQRT(1)
------- ------- ---------- ----------
2 0 1
- MOD :
This will give the remainder.
Syntax:
mod (value, divisor)
Ex:
SQL> select mod(7,4), mod(1,5), mod(null,null), mod(0,0), mod(-7,4) from dual;
MOD(7,4) MOD(1,5) MOD(NULL,NULL) MOD(0,0) MOD(-7,4)
-------- -------- -------------- -------- ---------
3 1 0 -3
- NVL :
This will substitutes the specified value in the place of null values.
Syntax:
nvl (null_col, replacement_value)
Ex:
SQL> select * from student; -- here for 3rd row marks value is null
NO NAME MARKS
-- ---- ---------
1 a 100
2 b 200
3 c
SQL> select no, name, nvl(marks,300) from student;
NO NAME NVL(MARKS,300)
-- ---- --------------
1 a 100
2 b 200
3 c 300
SQL> select nvl(1,2), nvl(2,3), nvl(4,3), nvl(5,4) from dual;
NVL(1,2) NVL(2,3) NVL(4,3) NVL(5,4)
-------- -------- -------- --------
1 2 4 5
SQL> select nvl(0,0), nvl(1,1), nvl(null,null), nvl(4,4) from dual;
NVL(0,0) NVL(1,1) NVL(null,null) NVL(4,4)
-------- -------- -------------- ----------
0 1 4
- POWER :
Power is the ability to raise a value to a given exponent.
Syntax:
power (value, exponent)
Ex:
SQL> select power(2,5), power(0,0), power(1,1), power(null,null), power(2,-5) from dual;
POWER(2,5) POWER(0,0) POWER(1,1) POWER(NULL,NULL) POWER(2,-5)
---------- ---------- --------- ----------------- ---------------
32 1 1 .03125
- EXP :
This will raise e value to the give power.
Syntax:
exp (value)
Ex:
SQL> select exp(1), exp(2), exp(0), exp(null), exp(-2) from dual;
EXP(1) EXP(2) EXP(0) EXP(NULL) EXP(-2)
-------- --------- ------ --------- ----------
2.71828183 7.3890561 1 .135335283
- LN :
This is based on natural or base e logarithm.
Syntax:
ln (value)
-- here value must be greater than zero which is positive only.
Ex:
SQL> select ln(1), ln(2), ln(null) from dual;
LN(1) LN(2) LN(NULL)
------ ------- ------------
0 .693147181
Ln and Exp are reciprocal to each other.
EXP (3) = 20.0855369
LN (20.0855369) = 3
- LOG :
This is based on 10 based logarithm.
Syntax:
log (10, value) -- here value must be greater than zero which is positive only.
Ex:
SQL> select log(10,100), log(10,2), log(10,1), log(10,null) from dual;
LOG(10,100) LOG(10,2) LOG(10,1) LOG(10,NULL)
----------- ----------- --------- -----------------
2 .301029996 0
LN (value) = LOG (EXP(1), value)
SQL> select ln(3), log(exp(1),3) from dual;
LN(3) LOG(EXP(1),3)
------- -----------------
1.09861229 1.09861229
- CEIL :
This will produce a whole number that is greater than or equal to the specified value.
Syntax:
ceil (value)
Ex:
SQL> select ceil(5), ceil(5.1), ceil(-5), ceil( -5.1), ceil(0), ceil(null) from dual;
CEIL(5) CEIL(5.1) CEIL(-5) CEIL(-5.1) CEIL(0) CEIL(NULL)
------- --------- -------- ---------- ------- ----------
5 6 -5 -5 0
- FLOOR :
This will produce a whole number that is less than or equal to the specified value.
Syntax:
floor (value)
Ex:
SQL> select floor(5), floor(5.1), floor(-5), floor( -5.1), floor(0), floor(null) from dual;
FLOOR(5) FLOOR(5.1) FLOOR(-5) FLOOR(-5.1) FLOOR(0) FLOOR(NULL)
-------- ---------- -------- ----------- --------- -----------
5 5 -5 -6 0
- ROUND :
This will rounds numbers to a given number of digits of precision.
Syntax:
round (value, precision)
Ex:
SQL> select round(123.2345), round(123.2345,2), round(123.2354,2) from dual;
ROUND(123.2345) ROUND(123.2345,0) ROUND(123.2345,2) ROUND(123.2354,2)
--------------- ----------------- ----------------- -----------------
123 123 123.23 123.24
SQL> select round(123.2345,-1), round(123.2345,-2), round(123.2345,-3),
round(123.2345,-4) from dual;
ROUND(123.2345,-1) ROUND(123.2345,-2) ROUND(123.2345,-3) ROUND(123.2345,-4)
------------------ ------------------ ------------------ ------------------
120 100 0 0
SQL> select round(123,0), round(123,1), round(123,2) from dual;
ROUND(123,0) ROUND(123,1) ROUND(123,2)
----------- ------------ ------------
123 123 123
SQL> select round(-123,0), round(-123,1), round(-123,2) from dual;
ROUND(-123,0) ROUND(-123,1) ROUND(-123,2)
------------ ------------- -------------
-123 -123 -123
SQL> select round(123,-1), round(123,-2), round(123,-3), round(-123,-1), round(-123,-
2), round(-123,-3) from dual;
ROUND(123,-1) ROUND(123,-2) ROUND(123,-3) ROUND(-123,-1) ROUND(-123,-2) ROUND(-123,-3)
------------- ------------- ------------- -------------- -------------- --------------
120 100 0 -120 -100 0
SQL> select round(null,null), round(0,0), round(1,1), round(-1,-1), round(-2,-2) from
dual;
ROUND(NULL,NULL) ROUND(0,0) ROUND(1,1) ROUND(-1,-1) ROUND(-2,-2)
---------------- ---------- ---------- ------------ ------------
0 1 0 0
- TRUNC :
This will truncates or chops off digits of precision from a number.
Syntax:
trunc (value, precision)
Ex:
SQL> select trunc(123.2345), trunc(123.2345,2), trunc(123.2354,2) from dual;
TRUNC(123.2345) TRUNC(123.2345,2) TRUNC(123.2354,2)
--------------- ----------------- -----------------
123 123.23 123.23
SQL> select trunc(123.2345,-1), trunc(123.2345,-2), trunc(123.2345,-3),
trunc(123.2345,-4) from dual;
TRUNC(123.2345,-1) TRUNC(123.2345,-2) TRUNC(123.2345,-3) TRUNC(123.2345,-4)
------------------ ------------------ ------------------ ------------------
120 100 0 0
SQL> select trunc(123,0), trunc(123,1), trunc(123,2) from dual;
TRUNC(123,0) TRUNC(123,1) TRUNC(123,2)
------------ ------------ -----------
123 123 123
SQL> select trunc(-123,0), trunc(-123,1), trunc(-123,2) from dual;
TRUNC(-123,0) TRUNC(-123,1) TRUNC(-123,2)
------------- ------------- -------------
-123 -123 -123
SQL> select trunc(123,-1), trunc(123,-2), trunc(123,-3), trunc(-123,-1), trunc(-123,2),
trunc(-123,-3) from dual;
TRUNC(123,-1) TRUNC(123,-2) TRUNC(123,-3) TRUNC(-123,-1) TRUNC(-123,2) TRUNC(-123,-3)
------------- ------------- ------------- -------------- ------------- --------------
120 100 0 -120 -123 0
SQL> select trunc(null,null), trunc(0,0), trunc(1,1), trunc(-1,-1), trunc(-2,-2) from dual;
TRUNC(NULL,NULL) TRUNC(0,0) TRUNC(1,1) TRUNC(-1,-1) TRUNC(-2,-2)
---------------- ---------- ---------- ------------ ----------------
0 1 0 0
- BITAND :
This will perform bitwise and operation.
Syntax:
bitand (value1, value2)
Ex:
SQL> select bitand(2,3), bitand(0,0), bitand(1,1), bitand(null,null), bitand(-2,-3) from dual;
BITAND(2,3) BITAND(0,0) BITAND(1,1) BITAND(NULL,NULL) BITAND(-2,-3)
----------- ---------- ----------- ---------------- -------------
2 0 1 -4
- GREATEST :
This will give the greatest number.
Syntax:
greatest (value1, value2, value3 ... valuen)
Ex:
SQL> select greatest(1, 2, 3), greatest(-1, -2, -3) from dual;
GREATEST(1,2,3) GREATEST(-1,-2,-3)
--------------- ------------------
3 -1
- If all the values are zeros then it will display zero.
- If all the parameters are nulls then it will display nothing.
- If any of the parameters is null it will display nothing.
- LEAST
This will give the least number.
Syntax:
least (value1, value2, value3 ... valuen)
Ex:
SQL> select least(1, 2, 3), least(-1, -2, -3) from dual;
LEAST(1,2,3) LEAST(-1,-2,-3)
------------ ---------------
1 -3
- If all the values are zeros then it will display zero.
- If all the parameters are nulls then it will display nothing.
- If any of the parameters is null it will display nothing.
- COALESCE :
This will return first non-null value.
Syntax:
coalesce (value1, value2, value3 ... valuen)
Ex:
SQL> select coalesce(1,2,3), coalesce(null,2,null,5) from dual;
COALESCE(1,2,3) COALESCE(NULL,2,NULL,5)
--------------- -----------------------
1 2
STRING FUNCTIONS
- Initcap
- Upper
- Lower
- Length
- Rpad
- Lpad
- Ltrim
- Rtrim
- Trim
- Translate
- Replace
- Soundex
- Concat ( ' || ' Concatenation operator)
- Ascii
- Chr
- Substr
- Instr
- Decode
- Greatest
- Least
- Coalesce
- INITCAP :
This will capitalize the initial letter of the string.
Syntax:
initcap (string)
Ex:
SQL> select initcap('computer') from dual;
INITCAP
--------
Computer
- UPPER :
This will convert the string into uppercase.
Syntax:
upper (string)
Ex:
SQL> select upper('computer') from dual;
UPPER
---------
COMPUTER
- LOWER :
This will convert the string into lowercase.
Syntax:
lower (string)
Ex:
SQL> select lower('COMPUTER') from dual;
LOWER
---------
computer
- LENGTH :
This will give length of the string.
Syntax:
length (string)
Ex:
SQL> select length('computer') from dual;
LENGTH
-------
8
- RPAD :
This will allows you to pad the right side of a column with any set of characters.
Syntax:
rpad (string, length [, padding_char])
Ex:
SQL> select rpad('computer',15,'*'), rpad('computer',15,'*#') from dual;
RPAD('COMPUTER' RPAD('COMPUTER'
--------------- ----------------
computer******* computer*#*#*#*
-- Default padding character was blank space.
- LPAD :
This will allows you to pad the left side of a column with any set of characters.
Syntax:
lpad (string, length [, padding_char])
Ex:
SQL> select lpad('computer',15,'*'), lpad('computer',15,'*#') from dual;
LPAD('COMPUTER' LPAD('COMPUTER'
--------------- ------------------
*******computer *#*#*#*computer
-- Default padding character was blank space.
- LTRIM :
This will trim off unwanted characters from the left end of string.
Syntax:
ltrim (string [,unwanted_chars])
Ex:
SQL> select ltrim('computer','co'), ltrim('computer','com') from dual;
LTRIM( LTRIM
-------- ---------
mputer puter
SQL> select ltrim('computer','puter'), ltrim('computer','omputer') from dual;
LTRIM('C LTRIM('C
---------- ----------
computer computer
-- If you haven't specify any unwanted characters it will display entire string.
- RTRIM :
This will trim off unwanted characters from the right end of string.
Syntax:
rtrim (string [, unwanted_chars])
Ex:
SQL> select rtrim('computer','er'), rtrim('computer','ter') from dual;
RTRIM( RTRIM
-------- ---------
comput compu
SQL> select rtrim('computer','comput'), rtrim('computer','compute') from dual;
RTRIM('C RTRIM('C
---------- ----------
computer computer
-- If you haven't specify any unwanted characters it will display entire string.
- TRIM :
This will trim off unwanted characters from the both sides of string.
Syntax:
trim (unwanted_chars from string)
Ex:
SQL> select trim( 'i' from 'indiani') from dual;
TRIM(
-----
ndian
SQL> select trim( leading'i' from 'indiani') from dual; -- this will work as LTRIM
TRIM(L
------
ndiani
SQL> select trim( trailing'i' from 'indiani') from dual; -- this will work as RTRIM
TRIM(T
------
Indian
- TRANSLATE
This will replace the set of characters, character by character.
Syntax:
translate (string, old_chars, new_chars)
Ex:
SQL> select translate('india','in','xy') from dual;
TRANS
--------
xydxa
- REPLACE :
This will replace the set of characters, string by string.
Syntax:
replace (string, old_chars [, new_chars])
Ex:
SQL> select replace('india','in','xy'), replace('india','in') from dual;
REPLACE REPLACE
----------- -----------
Xydia dia
- SOUNDEX :
This will be used to find words that sound like other words, exclusively used in where clause.
Syntax:
soundex (string)
Ex:
SQL> select * from emp where soundex(ename) = soundex('SMIT');
EMPNO ENAME JOB MGR HIREDATE SAL DEPTNO
----- ------ ----- ---- ------------ ----- --------
7369 SMITH CLERK 7902 17-DEC-80 500 20
- CONCAT :
This will be used to combine two strings only.
Syntax:
concat (string1, string2)
Ex:
SQL> select concat('computer',' operator') from dual;
CONCAT('COMPUTER'
------------------
computer operator
If you want to combine more than two strings you have to use concatenation operator (||).
SQL> select 'how' || ' are' || ' you' from dual;
'HOW'||'ARE
------------
how are you
- ASCII :
This will return the decimal representation in the database character set of the first
character of the string.
Syntax:
ascii (string)
Ex:
SQL> select ascii('a'), ascii('apple') from dual;
ASCII('A') ASCII('APPLE')
------------ ------------
97 97
- CHR :
This will return the character having the binary equivalent to the string in either the
database character set or the national character set.
Syntax:
chr (number)
Ex:
SQL> select chr(97) from dual;
CHR
-----
a
- SUBSTR :
This will be used to extract substrings.
Syntax:
substr (string, start_chr_count [, no_of_chars])
Ex:
SQL> select substr('computer',2), substr('computer',2,5), substr('computer',3,7) from
dual;
SUBSTR( SUBST SUBSTR
-------- ------- --------
omputer omput mputer
- If no_of_chars parameter is negative then it will display nothing.
- If both parameters except string are null or zeros then it will display nothing.
- If no_of_chars parameter is greater than the length of the string then it ignores and calculates based on the orginal string length.
- If start_chr_count is negative then it will extract the substring from right end.
1 2 3 4 5 6 7 8
C O M P U T E R
-8 -7 -6 -5 -4 -3 -2 -1
- INSTR :
This will allows you for searching through a string for set of characters.
Syntax:
instr (string, search_str [, start_chr_count [, occurrence] ])
Ex:
SQL> select instr('information','o',4,1), instr('information','o',4,2) from dual;
INSTR('INFORMATION','O',4,1) INSTR('INFORMATION','O',4,2)
--------------------------- ----------------------------
4 10
- If you are not specifying start_chr_count and occurrence then it will start search from
the beginning and finds first occurrence only.
- If both parameters start_chr_count and occurrence are null, it will display nothing.
- DECODE :
Decode will act as value by value substitution.
For every value of field, it will checks for a match in a series of if/then tests.
Syntax:
decode (value, if1, then1, if2, then2, ....... else);
Ex:
SQL> select sal, decode(sal,500,'Low',5000,'High','Medium') from emp;
SAL DECODE
----- ---------
500 Low
2500 Medium
2000 Medium
3500 Medium
3000 Medium
5000 High
4000 Medium
5000 High
1800 Medium
1200 Medium
2000 Medium
2700 Medium
2200 Medium
3200 Medium
SQL> select decode(1,1,3), decode(1,2,3,4,4,6) from dual;
DECODE(1,1,3) DECODE(1,2,3,4,4,6)
----------------- ------------------------
3 6
- If the number of parameters are odd and different then decode will display nothing.
- If the number of parameters are even and different then decode will display last value.
- If all the parameters are null then decode will display nothing.
- If all the parameters are zeros then decode will display zero.
- GREATEST :
This will give the greatest string.
Syntax:
greatest (strng1, string2, string3 ... stringn)
Ex:
SQL> select greatest('a', 'b', 'c'), greatest('satish','srinu','saketh') from dual;
GREAT GREAT
------- -------
c srinu
- If all the parameters are nulls then it will display nothing.
- If any of the parameters is null it will display nothing.
- LEAST :
This will give the least string.
Syntax:
greatest (strng1, string2, string3 ... stringn)
Ex:
SQL> select least('a', 'b', 'c'), least('satish','srinu','saketh') from dual;
LEAST LEAST
------- -------
a saketh
- If all the parameters are nulls then it will display nothing.
- If any of the parameters is null it will display nothing.
- COALESCE :
This will gives the first non-null string.
Syntax:
coalesce (strng1, string2, string3 ... stringn)
Ex:
SQL> select coalesce('a','b','c'), coalesce(null,'a',null,'b') from dual;
COALESCE COALESCE
----------- -----------
a a
DATE FUNCTIONS :
- Sysdate
- Current_date
- Current_timestamp
- Systimestamp
- Localtimestamp
- Dbtimezone
- Sessiontimezone
- To_char
- To_date
- Add_months
- Months_between
- Next_day
- Last_day
- Extract
- Greatest
- Least
- Round
- Trunc
- New_time
- Coalesce
Oracle default date format is DD-MON-YY.
We can change the default format to our desired format by using the following command.
SQL> alter session set nls_date_format = 'DD-MONTH-YYYY';
But this will expire once the session was closed.
- SYSDATE :
This will give the current date and time.
Ex:
SQL> select sysdate from dual;
SYSDATE
-----------
24-DEC-06
- CURRENT_DATE
This will returns the current date in the session's timezone.
Ex:
SQL> select current_date from dual;
CURRENT_DATE
------------------
24-DEC-06
- CURRENT_TIMESTAMP
This will returns the current timestamp with the active time zone information.
Ex:
SQL> select current_timestamp from dual;
CURRENT_TIMESTAMP
-----------------------------------------
24-DEC-06 03.42.41.383369 AM +05:30
- SYSTIMESTAMP
This will returns the system date, including fractional seconds and time zone of the
database.
Ex:
SQL> select systimestamp from dual;
SYSTIMESTAMP
------------------------------------
24-DEC-06 03.49.31.830099 AM +05:30
- LOCALTIMESTAMP
This will returns local timestamp in the active time zone information, with no time zone
information shown.
Ex:
SQL> select localtimestamp from dual;
LOCALTIMESTAMP
-----------------------------
24-DEC-06 03.44.18.502874 AM
- DBTIMEZONE
This will returns the current database time zone in UTC format. (Coordinated Universal Time)
Ex:
SQL> select dbtimezone from dual;
DBTIMEZONE
---------------
-07:00
- SESSIONTIMEZONE
This will returns the value of the current session's time zone.
Ex:
SQL> select sessiontimezone from dual;
SESSIONTIMEZONE
----------------
+05:30
- TO_CHAR
This will be used to extract various date formats.
The available date formats as follows.
Syntax:
to_char (date, format)
DATE FORMATS
D -- No of days in week
DD -- No of days in month
DDD -- No of days in year
MM -- No of month
MON -- Three letter abbreviation of month
MONTH -- Fully spelled out month
RM -- Roman numeral month
DY -- Three letter abbreviated day
DAY -- Fully spelled out day
Y -- Last one digit of the year
YY -- Last two digits of the year
YYY -- Last three digits of the year
YYYY -- Full four digit year
SYYYY -- Signed year
I -- One digit year from ISO standard
IY -- Two digit year from ISO standard
IYY -- Three digit year from ISO standard
IYYY -- Four digit year from ISO standard
Y, YYY -- Year with comma
YEAR -- Fully spelled out year
CC -- Century
Q -- No of quarters
W -- No of weeks in month
WW -- No of weeks in year
IW -- No of weeks in year from ISO standard
HH -- Hours
MI -- Minutes
SS -- Seconds
FF -- Fractional seconds
AM or PM -- Displays AM or PM depending upon time of day
A.M or P.M -- Displays A.M or P.M depending upon time of day
AD or BC -- Displays AD or BC depending upon the date
A.D or B.C -- Displays AD or BC depending upon the date
FM -- Prefix to month or day, suppresses padding of month or day
TH -- Suffix to a number
SP -- suffix to a number to be spelled out
SPTH -- Suffix combination of TH and SP to be both spelled out
THSP -- same as SPTH
Ex:
SQL> select to_char(sysdate,'dd month yyyy hh:mi:ss am dy') from dual;
TO_CHAR(SYSDATE,'DD MONTH YYYYHH:MI
------------------------------------
24 december 2006 02:03:23 pm sun
SQL> select to_char(sysdate,'dd month year') from dual;
TO_CHAR(SYSDATE,'DDMONTHYEAR')
-------------------------------
24 december two thousand six
SQL> select to_char(sysdate,'dd fmmonth year') from dual;
TO_CHAR(SYSDATE,'DD FMMONTH YEAR')
----------------------------------
24 december two thousand six
SQL> select to_char(sysdate,'ddth DDTH') from dual;
TO_CHAR(S
------------
24th 24TH
SQL> select to_char(sysdate,'ddspth DDSPTH') from dual;
TO_CHAR(SYSDATE,'DDSPTHDDSPTH
-----------------------------
twenty-fourth TWENTY-FOURTH
SQL> select to_char(sysdate,'ddsp Ddsp DDSP ') from dual;
TO_CHAR(SYSDATE,'DDSPDDSPDDSP')
------------------------------------
twenty-four Twenty-Four TWENTY-FOUR
- TO_DATE
This will be used to convert the string into data format.
Syntax:
to_date (date)
Ex:
SQL> select to_char(to_date('24/dec/2006','dd/mon/yyyy'), 'dd * month * day') from
dual;
TO_CHAR(TO_DATE('24/DEC/20
--------------------------
24 * december * Sunday
-- If you are not using to_char oracle will display output in default date format.
- ADD_MONTHS
This will add the specified months to the given date.
Syntax:
add_months (date, no_of_months)
Ex:
SQL> select add_months(to_date('11-jan-1990','dd-mon-yyyy'), 5) from dual;
ADD_MONTHS
-----------
11-JUN-90
SQL> select add_months(to_date('11-jan-1990','dd-mon-yyyy'), -5) from dual;
ADD_MONTH
----------
11-AUG-89
- If no_of_months is zero then it will display the same date.
- If no_of_months is null then it will display nothing.
- MONTHS_BETWEEN
This will give difference of months between two dates.
Syntax:
months_between (date1, date2)
Ex:
SQL> select months_between(to_date('11-aug-1990','dd-mon-yyyy'), to_date('11-jan-
1990','dd-mon-yyyy')) from dual;
MONTHS_BETWEEN(TO_DATE('11-AUG-1990','DD-MON-YYYY'),TO_DATE('11-JAN-1990','DD-MON-YYYY'))
---------------------------------------------------------------------------------------
7
SQL> select months_between(to_date('11-jan-1990','dd-mon-yyyy'), to_date('11-aug-
1990','dd-mon-yyyy')) from dual;
MONTHS_BETWEEN(TO_DATE('11-JAN-1990','DD-MON-YYYY'),TO_DATE('11-AUG-1990','DD-MON-YYYY'))
----------------------------------------------------------------------------------------
-7
- NEXT_DAY
This will produce next day of the given day from the specified date.
Syntax:
next_day (date, day)
Ex:
SQL> select next_day(to_date('24-dec-2006','dd-mon-yyyy'),'sun') from dual;
NEXT_DAY(
----------
31-DEC-06
-- If the day parameter is null then it will display nothing.
- LAST_DAY
This will produce last day of the given date.
Syntax:
last_day (date)
Ex:
SQL> select last_day(to_date('24-dec-2006','dd-mon-yyyy'),'sun') from dual;
LAST_DAY(
----------
31-DEC-06
- EXTRACT
This is used to extract a portion of the date value.
Syntax:
extract ((year | month | day | hour | minute | second), date)
Ex:
SQL> select extract(year from sysdate) from dual;
EXTRACT(YEARFROMSYSDATE)
------------------------
2006
-- You can extract only one value at a time.
- GREATEST
This will give the greatest date.
Syntax:
greatest (date1, date2, date3 ... daten)
Ex:
SQL> select greatest(to_date('11-jan-90','dd-mon-yy'),to_date('11-mar-90','dd-mon-
yy'),to_date('11-apr-90','dd-mon-yy')) from dual;
GREATEST(
-----------
11-APR-90
- LEAST
This will give the least date.
Syntax:
least (date1, date2, date3 ... daten)
Ex:
SQL> select least(to_date('11-jan-90','dd-mon-yy'),to_date('11-mar-90','dd-mon-
yy'),to_date('11-apr-90','dd-mon-yy')) from dual;
LEAST(
-----------
11-JAN-90
- ROUND
Round will rounds the date to which it was equal to or greater than the given date.
Syntax:
round (date, (day | month | year))
If the second parameter was year then round will checks the month of the given date in the
following ranges.
JAN -- JUN
JUL -- DEC
If the month falls between JAN and JUN then it returns the first day of the current year.
If the month falls between JUL and DEC then it returns the first day of the next year.
If the second parameter was month then round will checks the day of the given date in the
following ranges.
1 -- 15
16 -- 31
If the day falls between 1 and 15 then it returns the first day of the current month.
If the day falls between 16 and 31 then it returns the first day of the next month.
If the second parameter was day then round will checks the week day of the given date in
the following ranges.
SUN -- WED
THU -- SUN
If the week day falls between SUN and WED then it returns the previous sunday.
If the weekday falls between THU and SUN then it returns the next sunday.
- If the second parameter was null then it returns nothing.
- If the you are not specifying the second parameter then round will resets the time to the
begining of the current day in case of user specified date.
- If the you are not specifying the second parameter then round will resets the time to the
begining of the next day in case of sysdate.
Ex:
SQL> select round(to_date('24-dec-04','dd-mon-yy'),'year'), round(to_date('11-mar-
06','dd-mon-yy'),'year') from dual;
ROUND(TO_ ROUND(TO_
------------ ---------------
01-JAN-05 01-JAN-06
SQL> select round(to_date('11-jan-04','dd-mon-yy'),'month'), round(to_date('18-jan-
04','dd-mon-yy'),'month') from dual;
ROUND(TO_ ROUND(TO_
------------- ---------------
01-JAN-04 01-FEB-04
SQL> select round(to_date('26-dec-06','dd-mon-yy'),'day'), round(to_date('29-dec-
06','dd-mon-yy'),'day') from dual;
ROUND(TO_ ROUND(TO_
-------------- --------------
24-DEC-06 31-DEC-06
SQL> select to_char(round(to_date('24-dec-06','dd-mon-yy')), 'dd mon yyyy hh:mi:ss am')
from dual;
TO_CHAR(ROUND(TO_DATE('
------------------------
24 dec 2006 12:00:00 am
- TRUNC
Trunc will chops off the date to which it was equal to or less than the given date.
Syntax:
trunc (date, (day | month | year))
- If the second parameter was year then it always returns the first day of the current year.
- If the second parameter was month then it always returns the first day of the current month.
- If the second parameter was day then it always returns the previous sunday.
- If the second parameter was null then it returns nothing.
- If the you are not specifying the second parameter then trunk will resets the time to the begining of the current day.
Ex:
SQL> select trunc(to_date('24-dec-04','dd-mon-yy'),'year'), trunc(to_date('11-mar-
06','dd-mon-yy'),'year') from dual;
TRUNC(TO_ TRUNC(TO_
------------- ------------
01-JAN-04 01-JAN-06
SQL> select trunc(to_date('11-jan-04','dd-mon-yy'),'month'), trunc(to_date('18-jan-
04','dd-mon-yy'),'month') from dual;
TRUNC(TO_ TRUNC(TO_
------------- ------------
01-JAN-04 01-JAN-04
SQL> select trunc(to_date('26-dec-06','dd-mon-yy'),'day'), trunc(to_date('29-dec-06','dd-
mon-yy'),'day') from dual;
TRUNC(TO_ TRUNC(TO_
------------- --------
24-DEC-06 24-DEC-06
SQL> select to_char(trunc(to_date('24-dec-06','dd-mon-yy')), 'dd mon yyyy hh:mi:ss am')
from dual;
TO_CHAR(TRUNC(TO_DATE('
------------------------
24 dec 2006 12:00:00 am
- NEW_TIME
This will give the desired timezone's date and time.
Syntax:
new_time (date, current_timezone, desired_timezone)
Available timezones are as follows.
TIMEZONES
AST/ADT -- Atlantic standard/day light time
BST/BDT -- Bering standard/day light time
CST/CDT -- Central standard/day light time
EST/EDT -- Eastern standard/day light time
GMT -- Greenwich mean time
HST/HDT -- Alaska-Hawaii standard/day light time
MST/MDT -- Mountain standard/day light time
NST -- Newfoundland standard time
PST/PDT -- Pacific standard/day light time
YST/YDT -- Yukon standard/day light time
Ex:
SQL> select to_char(new_time(sysdate,'gmt','yst'),'dd mon yyyy hh:mi:ss am') from dual;
TO_CHAR(NEW_TIME(SYSDAT
------------------------
24 dec 2006 02:51:20 pm
SQL> select to_char(new_time(sysdate,'gmt','est'),'dd mon yyyy hh:mi:ss am') from dual;
TO_CHAR(NEW_TIME(SYSDAT
-----------------------
24 dec 2006 06:51:26 pm
- COALESCE
This will give the first non-null date.
Syntax:
coalesce (date1, date2, date3 ... daten)
Ex:
SQL> select coalesce('12-jan-90','13-jan-99'), coalesce(null,'12-jan-90','23-mar-98',null)
from dual;
COALESCE( COALESCE(
---------- ------------
12-jan-90 12-jan-90
MISCELLANEOUS FUNCTIONS
- Uid
- User
- Vsize
- Rank
- Dense_rank
- UID
This will returns the integer value corresponding to the user currently logged in.
Ex:
SQL> select uid from dual;
UID
-----
319
- USER
This will returns the login's user name.
Ex:
SQL> select user from dual;
USER
------
SAKETH
- VSIZE
This will returns the number of bytes in the expression.
Ex:
SQL> select vsize(123), vsize('computer'), vsize('12-jan-90') from dual;
VSIZE(123) VSIZE('COMPUTER') VSIZE('12-JAN-90')
---------- ----------------- ------------------
3 8 9
- RANK
This will give the non-sequential ranking.
Ex:
SQL> select rownum,sal from (select sal from emp order by sal desc);
ROWNUM SAL
---------- ----------
1 5000
2 3000
3 3000
4 2975
5 2850
6 2450
7 1600
8 1500
9 1300
10 1250
11 1250
12 1100
13 1000
14 950
15 800
SQL> select rank(2975) within group(order by sal desc) from emp;
RANK(2975)WITHINGROUP(ORDERBYSALDESC)
------------------------------------
4
- DENSE_RANK
This will give the sequential ranking.
Ex:
SQL> select dense_rank(2975) within group(order by sal desc) from emp;
DENSE_RANK(2975)WITHINGROUP(ORDERBYSALDESC)
------------------------------------------
3
CONVERSION FUNCTIONS
- Bin_to_num
- Chartorowid
- Rowidtochar
- To_number
- To_char
- To_date
- BIN_TO_NUM
This will convert the binary value to its numerical equivalent.
Syntax:
bin_to_num( binary_bits)
Ex:
SQL> select bin_to_num(1,1,0) from dual;
BIN_TO_NUM(1,1,0)
-----------------
6
- If all the bits are zero then it produces zero.
- If all the bits are null then it produces an error.
- CHARTOROWID
This will convert a character string to act like an internal oracle row identifier or rowid.
- ROWIDTOCHAR
This will convert an internal oracle row identifier or rowid to character string.
- TO_NUMBER
This will convert a char or varchar to number.
- TO_CHAR
This will convert a number or date to character string.
- TO_DATE
This will convert a number, char or varchar to a date.
GROUP FUNCTIONS
GROUP FUNCTIONS
Group functions will be applied on all the rows but produces single output.
- SUM
This will give the sum of the values of the specified column.
Syntax:
sum (column)
Ex:
SQL> select sum(sal) from emp;
SUM(SAL)
----------
38600
- AVG
This will give the average of the values of the specified column.
Syntax:
avg (column)
Ex:
SQL> select avg(sal) from emp;
AVG(SAL)
---------------
2757.14286
- MAX :
This will give the maximum of the values of the specified column.
Syntax:
max (column)
Ex:
SQL> select max(sal) from emp;
MAX(SAL)
----------
5000
- MIN
This will give the minimum of the values of the specified column.
Syntax:
min (column)
Ex:
SQL> select min(sal) from emp;
MIN(SAL)
----------
500
- COUNT
This will give the count of the values of the specified column.
Syntax:
count (column)
Ex:
SQL> select count(sal),count(*) from emp;
COUNT(SAL) COUNT(*)
-------------- ------------
14 14
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