In SQL, the wildcard character ‘%’ is used as a substitute for zero or more characters. It is often used in conjunction with the LIKE operator to perform pattern matching.

Let’s say we have a table called employees with columns for id, name, position, and salary. To select all the employees from the table, we can use the wildcard character like this:

SELECT * FROM employees;

The * represents all columns in the table, so this query will return all the rows and columns from the employees table.

Now, let’s say we want to retrieve all employees whose position starts with “developer”. We can use the wildcard at the end of the pattern to search for any characters after “developer”:

SELECT * FROM employees WHERE position LIKE 'developer%';

In this example, the % matches any characters that appear after “developer”. So, if we have employees with positions like “developer”, “senior developer”, or “lead developer”, they will all be returned by this query.

You can also use the wildcard at the beginning or both the beginning and end of a pattern to perform more flexible searches. For example, if you want to retrieve all employees with names containing the word “John”, you can use the wildcard at the beginning and end of the pattern:

SELECT * FROM employees WHERE name LIKE '%John%';

This query will match any names that have “John” appearing anywhere within them.

Wildcard characters can be a powerful tool for flexible querying in SQL. However, it’s important to use them carefully and be aware of the potential performance implications, especially when dealing with large datasets.

#SQL #Wildcard