SQL % Wildcard

What is the SQL % Wildcard?

The SQL % wildcard is used as a placeholder within the LIKE operator to represent zero or more characters in a text or string search. It's commonly used in SQL for pattern matching to find rows in a database where a particular part of a column value matches a specified pattern, and the rest of the value can be anything. The % wildcard is often used in conjunction with other characters or wildcards to perform flexible and powerful text searches.

When you would use it

You would use the SQL % wildcard when you need to search for rows in a database that match a specific pattern but allow for variability in the character sequence. It is particularly useful when you want to find values that contain certain substrings within a larger text, or when you want to perform searches with partial information.

Syntax

The % wildcard is typically used in conjunction with the LIKE operator. The syntax is as follows:

WHERE column_name LIKE pattern

• column_name: The name of the column you want to search in.
• pattern: The search pattern that may include % as a wildcard.

Parameter values

• column_name: The name of the column in which you want to search.
• pattern: The pattern you want to match against, where % represents zero or more characters.

Example query

Suppose you have a table named "products" with a column "product_name," and you want to find all products with names containing the word "apple" anywhere in the name. You can use the % wildcard with the LIKE operator as follows:

SELECT product_name
FROM products
WHERE product_name LIKE '%apple%';

In this query, % before and after "apple" allows for any characters before and after the word "apple."

Example table response

Assuming the "products" table contains the following data:

| product_name      |
| ----------------- |
| Apple iPhone 12   |
| Banana Phone      |
| Green Apples      |
| Apple Watch       |
| Pineapple Juice   |

The query mentioned earlier would return the following result:

| product_name      |
| ----------------- |
| Apple iPhone 12   |
| Green Apples      |
| Apple Watch       |
| Pineapple Juice   |

This result includes products with names that contain the word "apple" anywhere within the product_name.

Use cases

• Searching for values in text or string columns that match a specific pattern.
• Finding rows that contain specific substrings or keywords within text data.
• Performing partial text searches in a database.

SQL languages this is available for

The % wildcard with the LIKE operator is a widely supported feature and is available in most relational database management systems (RDBMS). It can be used in SQL systems such as MySQL, PostgreSQL, Oracle Database, SQL Server, SQLite, and others. The syntax and behavior are generally consistent across these systems, making it a versatile tool for pattern matching in SQL.