SQL CHARINDEX Function

The SQL CHARINDEX one of the String Function, which is used to find the index position of a specified expression from existing records.

TIP: The index position of the SQL CHARINDEX Function will start from 1, Not 0.

SQL CHARINDEX Function Syntax

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

SELECT CHARINDEX (ExpressionToFind, ExpressionToSearch, Starting_Position)
FROM [Source]

• ExpressionToFind: Please specify the valid Expression to find. The CHARINDEX function will search for this expression, if it finds the expression then it will return the index position otherwise, it will return 0.
• ExpressionToSearch: Please specify the valid Expression on which to want to perform search operation. The Sql Server CHARINDEX function will search this expression for ExpressionToFind.
• Starting_Position: This argument is optional. If you specify the starting position then CHARINDEX Function will start searching from this position otherwise, it will start searching from the beginning.

TIP: The CHARINDEX Function returns NULL, if ExpressionToFind or expressionToSearch is NULL.

For this CHARINDEX Function in SQL Server example, we are going to use the below shown data

SQL CHARINDEX Function Example

CHARINDEX Function is used to search for index position of a specific expression from the original string. The following query will show multiple ways to use the CHARINDEX function.

DECLARE @ExpressionToSearch varchar(100)
SET @ExpressionToSearch = 'Learn SQL Server 2014 with Examples in Tutorial Gateway' 

--Searching for a existent word --37
SELECT CHARINDEX ('in', @ExpressionToSearch) AS 'SQL CHARINDEX' 

--Searching from specific position – 20
SELECT CHARINDEX ('in', @ExpressionToSearch, 20) AS 'SQL CHARINDEX' 

--Searching for a non-existent word –0
SELECT CHARINDEX ('CHARINDEX', @ExpressionToSearch) AS 'SQL CHARINDEX'

OUTPUT

ANALYSIS

Below lines of code is used to declare a string variable and assigning the string data.

DECLARE @ExpressionToSearch varchar(100)
SET @ExpressionToSearch = 'Learn SQL Server 2014 with Examples in Tutorial Gateway' 

In the below statement, We used CHARINDEX function to find the index position of ‘in’ from the variable @ExpressionToSearch. We also assigned a new name to that result as ‘SQL CHARINDEX’ using ALIAS Column.

--Searching for an existent word --37
SELECT CHARINDEX ('in', @ExpressionToSearch) AS 'SQL CHARINDEX'

In the next line, We used the starting position argument inside the SQL CHARINDEX function. It means the function will start the search for ‘in’ from position 20, reduce the load.

--Searching from specific position – 20
SELECT CHARINDEX ('in', @ExpressionToSearch, 20) AS 'SQL CHARINDEX' 

In the next line, We searched for CHARINDEX, which is not existed inside the variable. That’s why it is returning 0

--Searching for a non-existent word –0
SELECT CHARINDEX ('CHARINDEX', @ExpressionToSearch) AS 'SQL CHARINDEX'

CHARINDEX Function Example 2

The Sql Charindex function also allows you to search for the expressions inside the column values. In this SQL Server example, We are going to find the index position of an Empty Space inside the Department Name column

SELECT [FirstName]
      ,[LastName]
      ,[DepartmentName]
      ,CHARINDEX (' ', [DepartmentName]) AS [Space Position]
 FROM [Employe]

OUTPUT

NOTE: If you observe the second record, Although it has Empty space at multiple position CHARINDEX displayed the value 4. This is because, CHARINDEX function will display the index position of a first occurrence and it does not care after that.

SQL CHARINDEX Function Example 3

In this example, We are going to find the index position of a @ symbol present in Email column using CHARINDEX function

SELECT [FirstName]
      ,[LastName]
      ,[DepartmentName]
      ,[Email]
      ,CHARINDEX ('@', [Email]) AS [@ Position]
 FROM [Employe]

OUTPUT

NOTE: We can’t use CHARINDEX on Image, Text and NText Data Types.