1. Open Source Server Side Scripting MySQL Functions
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Open Source Server Side Scripting
MySQL Functions
Open Source Server Side Scripting

2. Open Source Server Side Scripting
MySQL functions
MySQL has many functions available to alter or format the data stored in tables
when using a MySQL function specify a column name
case insensitive
no space between function name and parentheses
SELECT FUNCTION( column_name ) FROM table_name;
SELECT column1, FUNCTION( column2 ), column3 FROM table_name;
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3. Open Source Server Side Scripting
MySQL text functions
Function
Usage
Purpose
CONCAT( )
CONCAT( x, x, … )
Creates a new string of the form xy
CONCAT_WS( )
CONCAT( separator, x, y, … )
Creates a new string, with the separator between each string
CONV( )
CONV( n, from_base, to_base )
Converts numbers between different number bases
LEFT( )
LEFT( column, x )
Returns the leftmost x characters from a column’s value
RIGHT( )
RIGHT( column, x )
Returns the rightmost x characters from a column’s value
TRIM( )
TRIM( column )
Trims excess space from the beginning and end of the stored value
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4. MySQL text functions cont …
Usage
Purpose
UPPER( )
UPPER( column )
Capitalizes the stored string
LOWER( )
LOWER( column )
Turns the stored string into all lowercase
LPAD( )
LPAD( column, length, pad_character
Returns the string, left-padded with the designated character, to a designated length
RPAD( )
RPAD( column, length, pad_character
Returns the string, right-padded with the designated character, to a designated length
SUBSTRING( )
SUBSTRING( column, start, length )
Returns length characters from column beginning with start ( indexed from 0 )
LENGTH( )
LENGTH( column )
Returns the length of the value stored in the column
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5. MySQL text functions cont …
CONCAT( )
concatenates arguments
no default separator
CONCAT_WS( )
CONCAT With Separator
first argument is designated separator
SELECT CONCAT( last_name, ‘, ‘, first_name ) FROM users;
SELECT CONCAT_WS( ‘ ‘, first_name, last_name) FROM users ORDER BY last_name;
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6. Open Source Server Side Scripting
alias
alias
temporary renaming of table or column – allows for quick reference
used with keyword AS
case sensitive
once defined, query must use alias
SELECT CONCAT(last_name, ', ', first_name) AS fn FROM users ORDER BY fn;
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7. MySQL text functions cont …
CONV( )
converts numbers between different number bases
3 arguments
number to convert
base to convert from
base to convert to
SELECT CONV( ‘ffffff’, 16, 10 );
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8. MySQL text functions cont …
LEFT( )
returns the designated number of characters from the left of the value
RIGHT( )
returns the designated number of characters from the right of the value
SELECT LEFT( last_name, 3 ) FROM users ORDER BY last_name;
SELECT RIGHT( , 4 ) FROM users;
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9. MySQL text functions cont …
TRIM( )
strips all white space from the beginning and end of the value
similar functions include LTRIM( ) and RTRIM( ) to trim the white space from only beginning or end
TRIM( ) can also be used to trim specified prefixes or suffixes
SELECT TRIM( ) FROM users;
SELECT TRIM( LEADING FROM ); SELECT TRIM( TRAILING ‘room’ FROM ‘mushroom’ );
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10. MySQL text functions cont …
UPPER( )
converts the value to uppercase
LOWER( )
converts the value to lowercase
SELECT UPPER( last_name ) FROM users;
SELECT LOWER( last_name ) FROM users;
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11. MySQL text functions cont …
LPAD( )
returns the value, left padded with the designated string, the designated number of characters
RPAD( )
returns the value, right padded with the designated string, the designated number of characters
SELECT LPAD( last_name, 16, ‘*’ ) FROM users;
SELECT RPAD( last_name, 16, ‘*’ ) FROM users;
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12. MySQL text functions cont …
SUBSTRING( )
returns a substring of the value, the designated number of characters long, beginning at the designated position
LENGTH( )
Returns the length of the column value
SELECT SUBSTRING( last_name, 1, 3 ) AS ln FROM users ORDER BY ln;
SELECT LENGTH( first_name ), LENGTH( last_name ) FROM users ORDER BY last_name;
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13. MySQL numeric functions
Usage
Purpose
ABS( )
ABS( x )
Returns the absolute value of x
CEILING( )
CEILING( x )
Returns the next highest integer based on the value of x
FLOOR( )
FLOOR( x )
Returns the integer value of x
FORMAT( )
FORMAT( x, d )
Returns x formatted as a number with d decimal places, and commas every three spaces
MOD( )
MOD( x, y )
Returns modulus of dividing x by y
RAND( )
Returns a random number between 0 and 1.0
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14. MySQL numeric functions cont …
Usage
Purpose
ROUND( )
ROUND( x, d )
Returns the number x rounded to d decimal places
SIGN( )
SIGN( x )
Returns the sign of a x
SQRT( )
SQRT( x )
Calculates the square root of x
TRUNCATE( )
TRUNCATE( x, d )
Returns the number x, truncated to d decimals
LEAST( )
LEAST( x, y, … )
Passed 2 or more arguments, it returns the smallest
GREATEST( )
GREATEST( x, y, … )
Passed 2 or more arguments, it returns the largest
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15. MySQL numeric functions cont …
ABS( )
returns the absolute value
CEILING( )
returns the next highest integer, based on the value
SELECT ABS( -32 );
SELECT CEILING( );
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16. MySQL numeric functions cont …
FLOOR( )
returns the integer value of a number
FORMAT( )
returns a number formatted with the designated number of decimal places, and commas every three spaces
SELECT FLOOR( );
SELECT FORMAT( , 2 );
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17. MySQL numeric functions cont …
MOD( )
returns modulus
RAND( )
returns a random number between 0 and 1.0
SELECT MOD( 7, 4 );
SELECT RAND( );
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18. MySQL numeric functions cont …
ROUND( )
returns the number rounded to the designated decimal places
SIGN( )
returns a –1, 0, or 1 depending upon whether the number is negative, zero, or positive
SELECT ROUND( , 2 );
SELECT SIGN( -47 ); SELECT SIGN( 0 ); SELECT SIGN( 29 );
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19. MySQL numeric functions cont …
SQRT( )
calculates the square root of a number
TRUNCATE( )
returns a number, truncated to the designated number of decimals
SELECT SQRT( 64 );
SELECT TRUNCATE( , 2 );
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20. MySQL numeric functions cont …
LEAST( )
returns the smallest of at least 2 supplied arguments
GREATEST( )
returns the largest of at least 2 supplied arguments
SELECT LEAST( 2, 13, 8, 9);
SELECT GREATEST( 2, 13, 8, 9);
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21. MySQL date/time functions
Usage
Purpose
DATE( )
DATE( x )
Extracts the date part of a value
TIME( )
TIME( x )
Extracts the time part of a value
HOUR( )
HOUR( x )
Returns the hour of a stored value
MINUTE( )
MINUTE( x )
Returns the minute of a stored value
SECOND( )
SECOND( x )
Returns the second of a stored value
DAYNAME( )
DAYNAME( x )
Returns the name of the day of a stored value
DAYOFMONTH( )
DAYOFMONTH( x )
Returns the numerical day value of a stored value
MONTHNAME( )
MONTHNAME( x )
Returns the name of the month of a stored value
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22. MySQL date/time functions cont …
Usage
Purpose
MONTH( )
MONTH( x )
Returns the numerical month value of a stored value
YEAR( )
YEAR( x )
Returns the year of a stored value
ADDDATE( )
ADDDATE( x, INTERVAL t type )
Returns the value of x units added to the stored value
SUBDATE( )
SUBDATE( x, INTERVAL t type )
Returns the value of x units subtracted from the stored value
CURDATE( )
Returns the current date
CURTIME( )
Returns the current time
NOW( )
Returns the current date and time
UNIX_TIMESTAMP( )
UNIX_TIMESTAMP(date)
Returns the number of seconds since the Epoch
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23. MySQL date/time functions cont …
extracts the date part of a DATE or DATETIME expression
available in MySQL version 4.1.1
TIME( )
extracts the time part of a TIME or DATETIME expression
SELECT DATE( registration_date ) FROM users;
SELECT TIME( registration_date ) FROM users;
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24. MySQL date/time functions cont …
HOUR( )
returns the hour of a value, in the range 0 – 23
MINUTE( )
returns the minute of a value, in the range 0 – 59
SECOND( )
returns the second of a value, in the range 0 – 59
SELECT HOUR( registration_date ) FROM users;
SELECT MINUTE( registration_date ) FROM users;
SELECT SECOND( registration_date ) FROM users;
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25. MySQL date/time functions cont …
DAYNAME( )
returns the name of the weekday of a value
DAYOFMONTH( )
returns the day of the month of a value, in the range 1 – 31
MONTHNAME( )
returns the name of the month of a value
SELECT DAYNAME( registration_date ) FROM users;
SELECT DAYOFMONTH( registration_date ) FROM users;
SELECT MONTHNAME( registration_date ) FROM users;
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26. MySQL date/time functions cont …
MONTH( )
returns the month of a value, in the range 1 – 12
YEAR( )
returns the year of a value in the range 1000 – 9999
SELECT MONTH( registration_date ) FROM users;
SELECT YEAR( registration_date ) FROM users;
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27. MySQL date/time functions cont …
ADDDATE( )
used to perform calculations on date values
synonymous with DATE_ADD( )
prototype :
returns the value of date after x units of type have been added
ADDDATE( date, INTERVAL x type )
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28. MySQL date/time functions cont …
ADDDATE( )
types include
ADDDATE( ) type values
SECOND
YEAR
MINUTE
MINUTE_SECOND
HOUR
HOUR_MINUTE
DAY
DAY_HOUR
MONTH
YEAR_MONTH
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29. MySQL date/time functions cont …
ADDDATE( )
add 2 hours to a date/time value
add 3 weeks to a date/time value
add 18 months to a date/time value
SELECT ADDDATE( registration_date, INTERVAL 2 HOUR ) FROM users;
SELECT ADDDATE( registration_date, INTERVAL 21 DAY ) FROM users;
SELECT ADDDATE( registration_date, INTERVAL ‘1-6’ YEAR_MONTH ) FROM users;
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30. MySQL date/time functions cont …
SUBDATE( )
similar to ADDDATE( ), but subtracts from value
CURDATE( )
returns the current date
CURTIME( )
returns the current time
SELECT SUBDATE( registration_date, INTERVAL 1 DAY ) FROM users;
SELECT CURDATE( );
SELECT CURTIME( );
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31. MySQL date/time functions cont …
NOW( )
returns the current date and time
UNIX_TIMESTAMP( )
returns the number of seconds since the Unix Epoch
SELECT NOW( );
SELECT UNIX_TIMESTAMP( ‘ :46:40’ );
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