WHERE Clauses - (MariaDB Clauses)

The WHERE clause is a key feature of MariaDB SQL that allows users to filter results based on specific conditions. This clause is used in conjunction with the SELECT statement to retrieve data from one or more tables in a database.

Syntax

The basic syntax of a SELECT statement with a WHERE clause is as follows:

SELECT column1, column2, ...
FROM table_name
WHERE condition;

Here, column1, column2, and so on refer to the columns you want to retrieve data from. table_name is the name of the table that you want to retrieve data from. The condition is the criteria that determine which rows to retrieve.

Example

Here's an example of using the WHERE clause in a SELECT statement to filter results:

SELECT first_name, last_name
FROM employees
WHERE department = 'Sales' AND salary > 50000;

This statement retrieves the employees' first and last names from the employees table where the employee works in the "Sales" department and has a salary greater than $50,000.

Output

Running the SQL statement would output a list of employee first and last names who meet the specified criteria.

Explanation

In the above SQL code, the SELECT statement is retrieving the first_name and last_name columns from the employees table using the WHERE clause to only return the rows where the employee's department is "Sales" and their salary is greater than $50,000.

Use

Where clauses are useful for filtering data from a table or tables in a database, allowing users to obtain only those rows that meet specific criteria. This feature is particularly useful when dealing with large amounts of data or when complex search conditions have to be imposed on the data.

Important Points

• The WHERE clause is used in conjunction with the SELECT statement to filter data.
• The WHERE clause specifies the criteria that must be met to retrieve data from a table.
• Multiple conditions can be combined using logical operators such as AND and OR.
• The WHERE clause is useful for filtering data and retrieving only those rows that meet specific criteria.

Summary

In summary, the WHERE clause is a key feature of MariaDB SQL used in conjunction with the SELECT statement to filter data from a table or tables in a database. It allows users to retrieve only those rows that meet specific criteria. The WHERE clause is useful in cases where large amounts of data must be filtered or complex search conditions must be met.