Database Managment System - SQL Functions and Operators

1. SQL Functions
&
Operators
CS2258 – Database Management Systems Lab
R. Mohan Kumar
Assistant Professor / CSE
Saranathan College of Engineering

2. SQL Functions
 Numeric Functions
 Date Functions
 Text Functions
CS2258 – Database Management Systems Lab
Syntax
select <function_name> from dual;
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3. Numeric Functions
CS2258 – Database Management Systems Lab
FUNCTION NAME DESCRIPTION
ABS(x) Absolute value of the number “x”
CEIL(x) Integer value that is greater than (or) equal to “x”
FLOOR(x) Integer value that is lesser than (or) equal to “x”
TRUNC(x,y) Truncate values of “x” upto “y” decimal places.
ROUND(x,y) Rounded off value of “x” upto “y” decimal places.
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4. Numeric Functions
CS2258 – Database Management Systems Lab
FUNCTION NAME DESCRIPTION
MOD(x,y) Returns the result of X % Y (remainder)
POWER(x,y) Returns the value of X ^ Y
SQRT(x) Returns the square root value of X
LOG(x) Returns the Base 10 logarithm of X
SIGN(x) 1 if X is POSITIVE ; -1 if X is NEGATIVE ; 0 if X is ZERO
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5. Numeric Functions
CS2258 – Database Management Systems Lab
FUNCTION NAME DESCRIPTION
SIN(x) Returns the Sine value of X
COS(x) Returns the Cosine value of X
TAN(x) Returns the Tangent value of X
EXP(x) E raised to X exponent
LN(x) Returns the Natural Logarithm of X
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6. Numeric Functions
CS2258 – Database Management Systems Lab
FUNCTION NAME DESCRIPTION
MAX()
It selects the MAXIMUM value in the specified column.
Syntax:
Select MAX(<col_name>) from <table_name>;
MIN()
It selects the MINIMUM value in the specified column.
Syntax:
Select MIN(<col_name>) from <table_name>;
MEDIAN()
It returns the MEDIAN of all values in the given
column.
Syntax:
Select MEDIAN(<col_name>) from <table_name>;
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7. Numeric Functions
CS2258 – Database Management Systems Lab
FUNCTION NAME DESCRIPTION
AVG()
It returns the average of all values in the given column.
Syntax:
Select AVG(<col_name>) from <table_name>;
SUM()
It returns the sum of all values in the given column.
Syntax:
Select SUM(<col_name>) from <table_name>;
COUNT()
It returns the no. of rows in the given column.
Syntax:
Select COUNT(<col_name>) from <table_name>;
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8. Date Functions
FUNCTION NAME DESCRIPTION
SYSDATE Returns the systems current date.
ADD_MONTHS(date,n)
Returns a date value after adding in months
to the “date”.
MONTHS_BETWEEN(x1,x2)
Returns the number of months between dates
x1 and x2.
NEXTDAY(x, weekday)
Returns the next date of the “weekday” on or
after “x” occurs.
LAST_DAY(x) Returns the last date of the particular month.
CS2258 – Database Management Systems Lab
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9. Date Functions
FUNCTION NAME DESCRIPTION
SysTimeStamp
Returns the system date in TIMESTAMP
format.
To_char(date,format)
Returns the date value in given format.
Syntax:
Select to_char(sysdate,’mm/dd/yy’)
from dual;
CS2258 – Database Management Systems Lab
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10. String / Text Functions
FUNCTION NAME DESCRIPTION
UPPER(x) It converts the string ‘X’ to UPPER case
LOWER(x) It converts the string ‘X’ to LOWER case
RTRIM(x,y)
It returns the string after trimming all
occurrence of sub string ‘y’ from right side of
the input string ‘X’.
LTRIM(x,y)
It returns the string after trimming all
occurrence of sub string ‘y’ from left side of
the input string ‘X’.
LENGTH(x) Returns the length of the input string ‘X’
CS2258 – Database Management Systems Lab
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11. String / Text Functions
FUNCTION NAME DESCRIPTION
INITCAP(x)
It converts the first character of the input
string to UPPER case.
SUBSTR(x,m,n)
Returns the substring of given string starting
from position integer ‘m’ and length integer
‘n’.
TRANSLATE(x,new,old)
It converts the string by substituting the new
string in the place of old string.
ASCII(c) Returns the ASCII value of the character ‘c’.
CHR(number)
Returns the character for a ASCII value
‘number’.
CS2258 – Database Management Systems Lab
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12. Operators
 Arithmetic Operators
+ , - , * , /
 Comparison Operators
= , != , <, <=, >, >=
Like, In, Between And , Is Null
 Logical Operators
OR, AND, NOT
CS2258 – Database Management Systems Lab 12

13. Operators usage
 Arithmetic Operator
select 2 + 3 from dual;
select 10 - 5 from dual;
select salary + allowance from worker;
salary & allowance are the attributes of worker table.
update customer set balance = balance + balance * 0.075;
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14. Operators usage
 Comparison Operator
select * from customer where amount = 10000;
select * from customer where amount < 500;
select * from customer where age > 68;
update customer set interest_rate = 0.0925
where age >= 68;
delete from customer where balance <= 50;
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15. Operators usage
 Comparison Operator
select * from customer where cname LIKE ‘a%;
select * from customer where cname LIKE ‘%er;
select * from customer where cname IN (value1,value2,…);
delete from customer where balance BETWEEN 0 AND 50;
select * from customer where phoneno IS NULL;
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16. Operators usage
 Logical Operator
select * from customer where cname=‘john’ OR
cname=‘joshy’ ;
select * from customer where fname=‘joe’ AND
lname=‘parker’ ;
select * from customer where phoneno IS NOT NULL;
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CS2258 – Database Management Systems Lab