Hello and welcome to our ultimate guide on SQL Server Wildcard! If you’re new to SQL Server or just looking to learn more about wildcard, you’ve come to the right place. In this article, we’ll walk you through everything you need to know about using wildcard in SQL Server to improve your search queries, sort data, and refine your database.
What is SQL Server Wildcard?
First, let’s define what wildcard is. In SQL Server, wildcard is a special character or set of characters that can be used as a substitute for any other character(s) in a search query. This allows you to search for data based on a pattern rather than specific values.
There are two main types of wildcard in SQL Server: the percent sign (%) and the underscore (_). The percent sign represents any number of characters (including zero), while the underscore represents any single character.
Using the Percent Sign Wildcard in SQL Server
The percent sign wildcard is commonly used to search for values that contain a certain pattern of characters. For example, if you wanted to search for all customers whose last name begins with “Smi”, you could use the following query:
| Query | Result |
|---|---|
| SELECT * FROM customers WHERE last_name LIKE ‘Smi%’ | Returns all customers whose last name begins with “Smi”, such as Smith, Smiley, and Smirnov. |
Note that the percent sign can be used at the beginning, end, or in the middle of a search pattern. For example, if you wanted to search for all customers whose last name contains the letters “mi”, you could use the following query:
| Query | Result |
|---|---|
| SELECT * FROM customers WHERE last_name LIKE ‘%mi%’ | Returns all customers whose last name contains the letters “mi”, such as Smith, Schmidt, and Jamison. |
As you can see, the percent sign wildcard is a powerful tool for searching for data based on a pattern. It can be used in combination with other SQL keywords, such as SELECT, WHERE, and ORDER BY, to refine your search queries and sort your data.
Using the Underscore Wildcard in SQL Server
The underscore wildcard is similar to the percent sign wildcard, but it represents a single character rather than any number of characters. For example, if you wanted to search for all customers whose last name ends with “son” and is five letters long, you could use the following query:
| Query | Result |
|---|---|
| SELECT * FROM customers WHERE last_name LIKE ‘____son’ | Returns all customers whose last name ends with “son” and is five letters long, such as Wilson and Hudson. |
The underscore wildcard is useful for searching for values that have a specific length or format, such as phone numbers or email addresses. It can also be used in combination with other SQL keywords, such as WHERE and ORDER BY, to refine your search criteria and sort your data.
FAQs About SQL Server Wildcard
How do I escape a wildcard character in SQL Server?
If you need to search for a literal percent sign or underscore in your data, you can escape the wildcard character by using the escape character (\). For example, if you wanted to search for all customers whose last name contains a percent sign, you could use the following query:
| Query | Result |
|---|---|
| SELECT * FROM customers WHERE last_name LIKE ‘%\%%’ | Returns all customers whose last name contains a percent sign, such as Smith and Jones. |
Similarly, if you wanted to search for all customers whose last name contains an underscore, you could use the following query:
| Query | Result |
|---|---|
| SELECT * FROM customers WHERE last_name LIKE ‘%\_%’ | Returns all customers whose last name contains an underscore, such as Johnson and Brown. |
Can I use wildcard in other SQL commands besides SELECT?
Yes, you can use wildcard in other SQL commands, such as INSERT, UPDATE, and DELETE. For example, if you wanted to update all customers whose last name begins with “Smi” to have a new email address, you could use the following query:
| Query | Result |
|---|---|
| UPDATE customers SET email = ‘newemail@example.com’ WHERE last_name LIKE ‘Smi%’ | Updates the email address for all customers whose last name begins with “Smi”. |
Just be sure to use wildcard in combination with other SQL keywords, such as WHERE and SET, to ensure that you’re updating or deleting the correct data.
Are there any risks to using wildcard in SQL Server?
While wildcard can be a powerful tool for querying and sorting data in SQL Server, it can also be prone to errors and unintended results. For example, if you use a search pattern that is too broad, you may inadvertently include data that you didn’t intend to include.
To minimize the risks of using wildcard in SQL Server, it’s important to carefully plan your search queries and test them thoroughly. You can also use other SQL keywords, such as WHERE and ORDER BY, to refine your search criteria and sort your data in a more precise manner.
Conclusion
SQL Server Wildcard is a powerful tool for querying and sorting data in SQL Server. It allows you to search for data based on a pattern rather than specific values, which can save you time and effort when working with large databases.
In this article, we’ve walked you through everything you need to know about using wildcard in SQL Server, including how to use the percent sign and underscore wildcards in your search queries, how to escape wildcard characters, and how to use wildcard in other SQL commands besides SELECT.
We hope that this guide has been helpful in improving your SQL Server skills and refining your database queries. If you have any further questions or would like more information, please feel free to reach out to us!