Display the Length and First 3 Characters of Ename Column

In SQL, string manipulation is a fundamental operation, and sometimes, we need to extract specific portions of a string to analyze or present data. One of the common requirements is to display the length of a string and retrieve the first few characters. For this, SQL provides functions like LEN() and LEFT().

In this article, we will explain how to use these functions to display the length and the first 3 characters from the Ename column in the Emp table, using MSSQL (Microsoft SQL Server) as the server.

Understanding the LEN() Function

The LEN() function is used to find the total number of characters in a string, excluding trailing spaces. It is commonly used in SQL Server to evaluate the length of a string column or a literal string.

Syntax

LEN(string)

string: The input string or column name for which you want to calculate the length.

Understanding the LEFT() Function

The LEFT() function extracts the first n characters from a given string, starting from the leftmost position. It is particularly useful for slicing strings for display or categorization purposes.

Syntax

LEFT(string, n)

Key Terms:

• string: The input string or column name from which you want to extract characters.
  
• n: The number of characters to extract from the beginning of the string.

Step-by-Step Guide to Apply String Functions in SQL

Let’s implement these functions using the Emp table in a database named GeeksforGeeks. This guide will walk us through creating the database, inserting data, and executing queries step by step.

Step 1: Creating a Database

To begin, we first need to create a database to hold our table. We can name our database anything, but GeeksforGeeks is used here for example purposes.

Query

CREATE DATABASE GeeksforGeeks

Step 2: Using the Database

To use the GeeksforGeeks database use the below command: This command selects the GeeksforGeeks database, making it the active database for subsequent operations.

Query

USE GeeksforGeeks;

Step 3: Creating the Table

Now, we will create a table called Emp that holds employee information such as Employee ID (E_id), Employee Name (Ename), Department (Edept), Age (E_age), and Sex (E_sex).

CREATE TABLE Emp
(
E_id varchar(20),
Ename varchar(20),
Edept varchar(20),
E_age INT,
E_sex varchar(8)
);

Step 4: Inserting data into the table 

Inserting rows into the Emp table using the following SQL query. This INSERT INTO statement adds five rows to the Emp table. Each row contains the details of an employee.

Query:

 INSERT INTO Emp VALUES('E00001','JHONNY','BACKEND DEVELOPER',26,'male'),
 ('E00002','DARSHI','MARKETING',27,'male'),
('E00003','JASMINE','FRONTEND DEVELOPER',37,'female'),
('E00004','LILLY','FULL STACK DEVELOPER',47,'female'),
('E00005','RONALD','UI DEVELOPER',26,'male')

Step 6: Verifying the Inserted Data

After inserting the data, you can use the following SELECT statement to view the contents of the Emp table:

Query:

SELECT* FROM Emp

Output

Step 7: Query to Display the Length and First 3 Characters of Ename Column

Now, let’s use the LEN() and LEFT() functions to determine the length of each employee's name and extract the first three characters from the Ename column. This query helps analyze string data effectively by combining length and substring extraction functionalities.

Query:

SELECT LEN(Ename) AS LengthofEname,
LEFT(Ename,3) AS FirstThree FROM Emp

Output

Explanation:

In this result, we can see that the first 3 characters of the Ename column are displayed, and the length of each employee's name is also shown.

Step 8: Query to Display the Length and Last 3 Characters of Ename Column

In this step, we use the LEN() function to calculate the length of each employee name and the RIGHT() function to extract the last three characters from the Ename column. This approach is useful for analyzing the trailing part of string data in the table.

Query:

SELECT LEN(Ename) AS LengthofEname,
RIGHT(Ename,3) AS LastThree FROM Emp

Output

Explanation:

• The LEN(Ename) function still returns the total length of the string.
• The RIGHT(Ename, 3) function extracts the last 3 characters from the Ename column.

Conclusion

In this article, we have demonstrated how to use SQL string functions like LEN(), LEFT(), and RIGHT() to manipulate string data in SQL Server (MSSQL). These functions are useful for extracting specific portions of a string, such as displaying the length or the first/last few characters. Whether we're working with employee data, product names, or customer details, these techniques will help us efficiently process and analyze text data.