SQL CHAR Function

The SQL CHAR function is a SQL String Function used to convert the user specified integer value (ASCII code) to a character. This SQL CHAR function is exactly opposite to the ASCII Function

SQL CHAR Function Syntax

The syntax of the SQL Server CHAR Function is as shown below:

SELECT CHAR (int_Expression)
FROM [Source]

int_Expression: Please specify the valid integer value or Expression for which you want to find the character. The specified integer value range should be between 0 and 255, and if you exceed the range, then the CHAR function will return NULL as output.

TIP: Please refer ASCII Table to check the ASCII codes of each character.

The SQL Server CHAR function can be used to insert the control characters. The below table will show you some of the most frequently used control characters.

Return Type

This function will return CHAR(1)

SQL CHAR Function Example 1

The CHAR Function convert the given integer value to the character. The following query may show you multiple ways to use this CHAR function.

DECLARE @x INT
DECLARE @y INT
DECLARE @z CHAR(2)

-- Initialize the variables.  
SET @x = 75
SET @y = 105
SET @z = 'T'

SELECT CHAR(@x) AS Result1,
       CHAR(@y) AS Result2,
       CHAR(ASCII(@Z)) AS Result3;

SELECT CHAR(204) AS Result4;  

SELECT CHAR('71') AS Result5;

OUTPUT

ANALYSIS

Here, we are finding the characters at the integer values 75 and 105.

SELECT CHAR(@x) AS Result1,
       CHAR(@y) AS Result2,
       CHAR(ASCII(@Z)) AS Result3;

In the next line, We used the integer value directly inside the Sql Server CHAR function

SELECT CHAR(204) AS Result4;

You can see from the below statement, We specified the string value 71, but SQL is implicitly converting string 71 to integer 71 and returning the character at 71.

SELECT CHAR('71') AS Result5;

CHAR Function Example 2

In this example, We are going to use the CHAR function inside the WHILE LOOP. I suggest you refer both the SUBSTRING and WHILE LOOP articles to know the query execution.

DECLARE @i INT, 
        @int_expression VARCHAR(50);  

-- Initialize the variables.  
SET @i = 1;  
SET @int_expression = '959871737882';
 
WHILE @i <= LEN(@int_expression)
	BEGIN
		SELECT SUBSTRING(@int_expression, @i, 2) AS [ASCII_Value],
			CHAR(SUBSTRING(@int_expression, @i, 2)) AS [ASCII_Value]
		SET @i = @i + 2
	END;

OUTPUT