SQL Server provides the REPLICATE function to create a sequence of a string in repetition. For example, we can tell SQL Server to repeat the character 0 3 times to get
000. In this article, we will learn how to use the REPLICATE function in SQL Server.
The basic syntax of a REPLICATE is as follows:
SELECT REPLICATE(string_name, count);
For this, we will be using docker. This is recommended for more than just using SQL Server. To find how to install docker go here: https://docs.docker.com/engine/install/
Now create a file called
docker-compose.yml and add the following.
version: "3.9" services: db: image: "mcr.microsoft.com/mssql/server" ports: - 1433:1433 environment: SA_PASSWORD: "Your_password123" ACCEPT_EULA: "Y"
Open a terminal and go to the folder the file is located. Then run the following.
If you are looking for another good reference, you can check here: https://docs.docker.com/samples/aspnet-mssql-compose/.
The basic example is straight forward. We can run the REPLICATE function with a string and assign a number of times to replicate.
SELECT REPLICATE('Hello ', 6) as string;
|Hello Hello Hello Hello Hello Hello|
That's the gist of using the replicate function. We can now move to a larger example of using REPLICATE with a table. One common use case is to add padding with strings to align values in a table.
We start by creating an employee table to work with.
CREATE TABLE employees ( first_name VARCHAR (50) NOT NULL, last_name VARCHAR (50) NOT NULL );
Next, we can insert some data.
insert into employees (first_name, last_name) values ('Keith', 'Holliday'), ('Jon', 'Doe'), ('Jane', 'Doe');
And, we can preview the data like so.
SELECT * FROM employees;
Now, we can select all the first names and add
x as a padding to align all the values. This is common when marking products or building usernames that all require the same number of characters.
The count will be the number of characters we require, 10, minus the number of characters in the string.
select CONCAT( REPLICATE('x', 10 - len(first_name)), first_name ) as username from employees e;