HKOI 2004 Team Training Data Processing 1 & String Functions (Intermediate Level)
String functions
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Transcript of String functions
Kumar Krishnan
Thanks to
Shivakumar .U
Sunil V.M
Lokesh
Spoorthi
Job John
Vinod Raj
Perform operations on a string (char or varchar) input value and return a string or numeric value.
In simple Terms the STRING FUNCTIONS are used to used primarily for string manipulation
ASCII
CHAR
SUBSTR-(SUBSTRING)
REPLACE
REPLICATE
UPPER
LEN-(LENGTH)
CHARINDEX
PATINDEX
LEFT
RIGHT
LOWER
LTRIM
STUFF
DIFFERENCE
CONCAT
UNICODE
SPACE
STR
UNICODE
SOUNDEX
QOUTENAME
NCHAR
RTRIM
REVERSE
ASCII : ASCII (character_expression)
Arguments: Is an expression of the type char or varchar.
Returns: INT
Ex: SELECT ASCII (‘A’) ------ Returns: 97
CHAR : CHAR (character_expression)
Arguments: Is an integer from 0 through 255. NULL is returned if the integer expression is not in this range.
Returns : CHAR
Ex: SELECT CHAR (101) ----- Returns: E.
CHARINDEX ( expressionToFind ,expressionToSearch , start location )
Arguments:
expressionToFind
Is a character expression that contains the sequence to be found. expressionToFind is limited to 8000 characters.
expressionToSearch
Is a character expression to be searched.
start location
Is an integer or bigint expression at which the search starts. If start location is not specified, is a negative number, or is 0, the search starts at the beginning of expressionToSearch.
Return Types:
bigint if expressionToSearch is of the varchar(max), nvarchar(max), or varbinary(max) data types; otherwise, int.
Ex: SELECT CHARINDEX ('k','kumar',1) ------ 1
CONCAT : CONCAT(string_value1,string_value2,[string value])
Arguments:
String value
A string value to concatenate to the other values.
Return:
String, the length and type of which depend on the input.
Ex : SELECT CONCAT ( 'Happy ', 'Birthday ', 11, '/', '25‘)
Note : CONCAT is Available in the SQL Server 2012
DIFFERENCE ( character_expression , character_expression)
Arguments:
character_expression
Is an alphanumeric expression of character data. character_expression can be a constant, variable, or column.
Returns:
INT
Ex: SELECT DIFFERENCE ( ‘Kumar’ , ‘umar’ ) ----- 3
The return value ranges from 0 through 4: 0 indicates weak or no similarity, and 4 indicates strong similarity or the same values.
LEFT : (character_expression , integer_expression)
Arguments:
character_expression
Is an expression of character or binary data.
integer_expression
Is a positive integer that specifies how many characters of the character_expression will be return
Return Types:
Returns varchar when character_expression is a non-Unicode character data type.
Returns nvarchar when character_expression is a Unicode character data type.
Ex : SELECT LEFT(‘KUMAR’,3) ----- KUM
RIGHT : RIGHT (character_expression , integer_expression)
Arguments
character_expression
Is an expression of character or binary data. character_expression can be a constant, variable, or column.
Integer_expression
Is a positive integer that specifies how many characters of character_expression will be returned
Return Types
Returns varchar when character_expression is a non-Unicode character data type.
Returns nvarchar when character_expression is a Unicode character data type.
Ex: SELECT RIGHT(‘KUMAR’,3) ----- MAR
LEN : LEN(( string expression )
Arguments
string expression
Is the string expression to be evaluated. string expression can be a constant, variable, or column of either character or binary data.
Return Types
bigint if expression is of the varchar(max), nvarchar(max) or varbinary(max) data types; otherwise, int.
EX: SELECT LEN ( ‘KUMAR’) ------ 5
LTRIM : LTRIM ( character_expression )
Arguments
character_expression
Is an expression of character or binary data. character_expression can be a constant, variable, or column.
Return Type
varchar or nvarchar
Ex: SELECT LTRIM (‘ KUMAR’) --- KUMAR
REPLACE: REPLACE( string,string_pattern,string_replacement)
Arguments
string_expression
Is the string expression to be searched. string_expression can be of a character or binary data type.
string pattern
Is the substring to be found. string pattern can be of a character or binary data type.
string replacement
Is the replacement string. string replacement can be of a character or binary data type.
Return Types
Returns nvarchar if one of the input arguments is of the nvarchar data type.
Ex: SELECT (‘KUMAR’,’U’,’UU’) ---- KUUMAR
SUBSTRING : SUBSTRING ( expression ,start , length )
Arguments:
Expression Is a character, binary, text, ntext, or image expression.
start
Is an integer or bigint expression that specifies where the returned characters start. If start is less than 1,
length
Is a positive integer or bigint expression that specifies how many characters of the expression will be returned.
Return Types
Returns character data if expression is one of the supported character data types
Ex: SELECT SUBSTRING ( ‘MY NAME IS KUMAR’ ,3,3) ---- NAM
STUFF:STUFF (character_expression, start, length, replace_exprn)
Arguments
Is an expression of character data. character_expression can be a constant, variable, or column of either character or binary data.
start
Is an integer value that specifies the location to start deletion and insertion
length
Is an integer that specifies the number of characters to delete
Replace expression
Is an expression of character data. character_expression can be a constant, variable, or column of either character or binary data
Ex: SELECT STUFF( ‘KUMAR’,1,3,’NAMASK’ ) ------NAMASKAR