SQL DELETE Statement and Syntax

SQL Delete Syntax

The DELETE statement is a powerful feature in SQL databases that allows you to remove specific information from your tables. However, it is crucial to exercise caution when using DELETE, as once executed, the data cannot be recovered unless you restore the database from a backup.

Basic Syntax

The simplest form of a DELETE query consists of the DELETE keyword followed by the table name. For instance, DELETE FROM MyTable; would delete all rows within MyTable.

DELETE FROM MyTable;

Conditional Deletion

To delete specific information based on a condition, you can utilize the DELETE statement along with the WHERE clause. The WHERE clause is used to specify which rows should be removed from the table by referencing a condition. For example, if you want to delete all employees who are older than 30 years, you can use the following query:

DELETE FROM Employees WHERE Age > 30;

This query will remove all records where the Age column value exceeds 30.

Examples

Example 1

Let's consider a simple user list in a database. We have a table named "Users" with UserID, FirstName, LastName, Age columns. To remove users based on age:

DELETE FROM Users WHERE Age > 30;

Example 2

Assuming we had not already deleted William Garcia in the previous example, he would be removed based on our condition:

DELETE FROM Users WHERE Name = 'William';

Remember that these examples are just for illustration purposes. Always verify the need for such operations and consider data backups before running any DELETE queries.