Delete Data from a Table in SQL Server

Delete Data from a Table in SQL Server

Introduction:
In SQL Server, the DELETE statement is used to remove one or more rows from a table. It allows you to specify the conditions for deleting rows, and it's essential to use it with caution as it permanently removes data from the table.

Syntax:

sql
DELETE FROM table_name
WHERE condition;

Explanation:

• DELETE: This keyword specifies that we want to delete data from the table.
• FROM: Indicates the table from which we want to delete data.
• table_name: Replace this with the name of the table from which you want to delete the data.
• WHERE: This clause is optional but highly recommended to avoid unintentional deletion. It specifies the conditions that must be met for a row to be deleted. If no WHERE clause is specified, all rows in the table will be deleted.

Example:
Consider a table named "Customers" with the following structure:

sql
| CustomerID | CustomerName | Age | City      |
|------------|--------------|-----|-----------|
| 1          | John         | 30  | New York  |
| 2          | Alice        | 25  | San Diego |
| 3          | Bob          | 28  | Chicago   |
| 4          | Emma         | 22  | Houston   |

Suppose we want to delete the customer with CustomerID 2 from the table.

sql
DELETE FROM Customers
WHERE CustomerID = 2;

Explanation of the Example:
In this example, we are using the DELETE statement to remove the row with CustomerID 2 from the "Customers" table. The WHERE clause specifies the condition for deletion, ensuring that only the row with CustomerID 2 will be deleted. The resulting table will look like this:

sql
| CustomerID | CustomerName | Age | City      |
|------------|--------------|-----|-----------|
| 1          | John         | 30  | New York  |
| 3          | Bob          | 28  | Chicago   |
| 4          | Emma         | 22  | Houston   |

Important Note:
Always be cautious while using the DELETE statement, especially without a WHERE clause. Without a proper condition, all rows in the table will be deleted, leading to permanent data loss. Make sure to take backups and test your DELETE queries in a safe environment before applying them to critical databases.