SQL ASCII Function

The SQL ASCII is one of the SQL String Function, which is used to return the ASCII code of the left most character of a character expression. In this article we will show you, How to use/write ASCII in SQL Server 2014 with example.

SQL ASCII Function Syntax

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

SELECT ASCII (Character_Expression)
FROM [Source]

Character_Expression: Please specify the valid Expression for which you want to find the ASCII code. ASCII Function will return the ASCII code of the left most character of this expression. This Character_Expression can be a Char, or Varchar.

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

Return Type

This function will return INT

SQL ASCII Function Example 1

The ASCII Function is used to return the ASCII code of the leftmost character of the given expression. The following query will show multiple ways to use this function.

T-SQL CODE

DECLARE @i VARCHAR(25)
DECLARE @j INT

-- Initialize the variables.  
SET @i = 'a'
SET @j = 1

SELECT ASCII(@i) AS Result1,
	ASCII(@j) AS Result2 ;

SELECT ASCII('efgh') AS Result3;  

SELECT ASCII('789') AS Result4;

OUTPUT

ANALYSIS

Below lines of code is used to declare two variables of type VARCHAR and Integer type. Next, we assigning the string data ‘a’ and 1.

DECLARE @i VARCHAR(25)
DECLARE @j INT

-- Initialize the variables.  
SET @i = 'a'
SET @j = 1

From the below statement, you can see that we are finding the ASCII code of alphabet ‘a’ and integer 1. We also assigned new names to the result as ‘Result1’, and ‘Result2’ using ALIAS Column.

SELECT ASCII(@i) AS Result1,
       ASCII(@j) AS Result2 ;

In the next line, We used the ASCII function directly on group of characters (word). Here, ASCII function will return leftmost character (i.e., e) and that should be 101

SELECT ASCII('efgh') AS Result3;

You can see from the below statement, We used the ASCII function directly on integer. Here, ASCII function will return leftmost character (i.e., 7) and that should be 55

SELECT ASCII('789') AS Result4;

SQL ASCII Function Example 2

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

T-SQL CODE

DECLARE @i int, 
        @str char(16);  

-- Initialize the variables.  
SET @i = 1;  
SET @str = 'Tutorial Gateway'; 
 
WHILE @i <= DATALENGTH(@str)
	BEGIN
		SELECT SUBSTRING(@str, @i, 1) AS [Char_Value],
			ASCII(SUBSTRING(@str, @i, 1)) AS [ASCII_Result]
		SET @i = @i + 1
	END;

OUTPUT

SQL ASCII Function Example 3

In this example, we are going to implement the ASCII function on the column. For this, We are going to use the below shown data

Following statement will return the ASCII code of leftmost character in [FirstName] column and [LastName] column, and ASCII code of leftmost number in [YearlyIncome] column.

T-SQL CODE

SELECT [FirstName] 
      ,ASCII([FirstName]) AS [FN_ASCII] 
      ,[LastName]
      ,ASCII([LastName]) AS [LN_ASCII] 
      ,[Education]
      ,[Occupation]
      ,[YearlyIncome]
      ,ASCII([YearlyIncome]) AS [YI_ASCII]
      ,[Sales]
  FROM [SQL Tutorial].[dbo].[Employee]

OUTPUT

From the below screenshot you can observe that, 74 is the ASCII code of J, 89 is the ASCII code for Y, and 57 is the ASCII code for 9

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