SQL DELETE Statement

The SQL DELETE statement is used to remove specific rows from a table while keeping the table structure intact. It is different from DROP, which deletes the entire table.

• It removes rows based on conditions.
• Retains table schema, constraints, and indexes.
• Can delete a single row or all rows.

Example: First, we create a demo SQL database and table, on which we will use the SQL DELETE command.

Query:

DELETE FROM Employees
WHERE EmployeeID = 5;   

Output:

• This query deletes the row from the Employees table where the EmployeeID is 5.
• Only that specific record is removed; all other rows remain unchanged.

Syntax:

DELETE FROM table_name 
WHERE some_condition;

• Some_condition: A condition used to filter the rows you want to delete.
• table_name: The name of the table from which you want to delete the rows.

Note: We can delete single or multiple records using the WHERE clause; if it’s omitted, all records in the table are removed.

Examples of SQL DELETE Statement

Assume we have created a table named GFG_Employee in SQL, which contains the personal details of the Employee including their id, name, email and department etc. as shown below.

CREATE TABLE GFG_Employees (
id INT PRIMARY KEY,
name VARCHAR (20) ,
email VARCHAR (25),
department VARCHAR(20)
);

INSERT INTO GFG_Employees (id, name, email, department) VALUES
(1, 'Jessie', '[email protected]', 'Development'),
(2, 'Praveen', '[email protected]', 'HR'),
(3, 'Bisa', '[email protected]', 'Sales'),
(4, 'Rithvik', '[email protected]', 'IT'),
(5, 'Suraj', '[email protected]', 'Quality Assurance'),
(6, 'Om', '[email protected]', 'IT'),
(7, 'Naruto', '[email protected]', 'Development');

Select * From GFG_Employees

Output:

Example 1: Deleting Single Record

We can use the DELETE statement with a condition to delete a specific row from a table. The WHERE clause ensures only the intended record is removed. We can delete the records named Rithvik by using the below query:

Query:

DELETE FROM GFG_Employees 
WHERE NAME = 'Rithvik';   

Output:

Example 2: Deleting Multiple Records

To delete multiple records, you can specify a condition that matches several rows. Let's delete the rows from the table  GFG_Employees where the department is "Development". This will delete 2 rows (the first row and the seventh row).

Query:

DELETE FROM GFG_Employees 
WHERE department = 'Development'; 

Output

Example 3: Delete All Records from a Table

If we need to delete all records from the table, we can omit the WHERE clause, or alternatively use the DELETE statement with an asterisk (*) to denote all rows.

Query:

DELETE FROM GFG_Employees;
Or
DELETE * FROM GFG_Employees;

Output:

All of the records in the table will be deleted, there are no records left to display. The table GFG_Employees  will become empty.

Rolling Back DELETE Operations

Since the DELETE statement is a DML operation, it can be rolled back when executed in a statement. If you accidentally delete records or need to repeat the process, you can use the ROLLBACK command.

Query:

BEGIN TRANSACTION;
DELETE FROM GFG_Employees;
WHERE department = 'Development';

-- If needed, you can rollback the deletion
ROLLBACK;

Explanation: The ROLLBACK command will undo the changes made by the DELETE statement, effectively restoring the records that were deleted during the transaction.

Suggested Quiz

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5 Questions

What does the DELETE statement remove?

• A

  Only specific rows

• B

  Entire table structure

• C

  Constraints and indexes

• D

  Database schema

Explanation:

DELETE removes selected rows while keeping the table structure intact.

What happens if the WHERE clause is omitted in a DELETE statement?

• A

  SQL throws an error

• B

  Only NULL rows get deleted

• C

  All rows in the table are deleted

• D

  Nothing is deleted

Explanation:

Without WHERE, DELETE clears all records, leaving the table empty but still existing.

Which query deletes all employees in the 'Development' department?

• A

  DELETE GFG_Employees WHERE dept = 'Development';

• B

  REMOVE FROM GFG_Employees WHERE department = 'Development';

• C

  DROP FROM GFG_Employees WHERE department = 'Development';

• D

  DELETE FROM GFG_Employees WHERE department = 'Development';

Explanation:

DELETE FROM table WHERE condition removes multiple matching rows, as shown in Example.

Which operation can be rolled back when executed inside a transaction?

• A

  DROP

• B

  TRUNCATE

• C

  DELETE

• D

  ALTER TABLE

Explanation:

DELETE is a DML operation, so it supports ROLLBACK when executed inside a transaction.

What is the effect of this query?

DELETE FROM GFG_Employees WHERE name = 'Alice';

• A

  Deletes all IT employees

• B

  Deletes only the row where name = 'Alice'

• C

  Deletes all rows

• D

  Deletes only NULL rows

Explanation:

The WHERE clause ensures only the matching record (name = 'Alice') is removed.

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