Built in string functions in sql server

In SQL server, Function can be broadly divided into 2 categoris 1. Built-in functions 2. User Defined functions

Here we will look at the most common string functions available .There are several built-in functions..in sql server.

ASCII(Character_Expression) - Returns the ASCII code of the given character expression.
To find the ASCII Code of capital letter 'A'
Example: Select ASCII('A')
Output: 65

CHAR(Integer_Expression) - Converts an int ASCII code to a character. The Integer_Expression, should be between 0 and 255.

for example: 

Declare @Number int

Set @Number = 1
While(@Number <= 1255)
Begin
select CHAR(@Number)
Set @Number = @Number + 1
End
output:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Printing uppercase alphabets using CHAR() function:
Declare @Number int
Set @Number = 65
While(@Number <= 90)
Begin
 Print CHAR(@Number)
 Set @Number = @Number + 1
End

Printing lowercase alphabets using CHAR() function:
Declare @Number int
Set @Number = 97
While(@Number <= 122)
Begin
 Print CHAR(@Number)
 Set @Number = @Number + 1
End


Another way of printing lower case alphabets using CHAR() and LOWER() functions.
Declare @Number int
Set @Number = 65
While(@Number <= 90)
Begin
 Print LOWER(CHAR(@Number))
 Set @Number = @Number + 1
End

LTRIM(Character_Expression) - Removes blanks on the left handside of the given character expression.

Example: Removing the 3 white spaces on the left hand side of the '   Hello' string using LTRIM() function.
Select LTRIM('   Hello')
Output: Hello

RTRIM(Character_Expression) - Removes blanks on the right hand side of the given character expression.

Example: Removing the 3 white spaces on the left hand side of the 'Hello   ' string using RTRIM() function.
Select RTRIM('Hello   ')
Output: Hello

Example: To remove white spaces on either sides of the given character expression, use LTRIM() and RTRIM() as shown below.
Select LTRIM(RTRIM('   Hello   '))
Output: Hello

LOWER(Character_Expression) - Converts all the characters in the given Character_Expression, to lowercase letters.

Example: Select LOWER('CONVERT This String Into Lower Case')
Output: convert this string into lower case

UPPER(Character_Expression) - Converts all the characters in the given Character_Expression, to uppercase letters.
Example: Select UPPER('CONVERT This String Into upper Case')
Output: CONVERT THIS STRING INTO UPPER CASE

REVERSE('Any_String_Expression') - Reverses all the characters in the given string expression.
Example: Select REVERSE('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
Output: ZYXWVUTSRQPONMLKJIHGFEDCBA

LEN(String_Expression) - Returns the count of total characters, in the given string expression, excluding the blanks at the end of the expression.

Example: Select LEN('SQL Functions   ')
Output: 13