DELETE
Function Description
The DELETE statement is used to delete rows that meet specified conditions from a database table.
Precautions
Omitting the WHERE clause will delete all rows in the table. Proceed with caution. It is advised to use SELECT to verify the data to be deleted before execution, and to run the operation within a transaction so that it can be rolled back if necessary.
Syntax
sql
DELETE FROM [schema.]table_name [WHERE condition];Parameter Description
| Name | Description |
|---|---|
| DELETE FROM ... | Keyword indicating that a delete operation is to be performed. |
| [schema.]table_name | Name of the target table from which data is to be deleted. |
| [WHERE condition] | (Optional) Specifies the condition for which rows to delete. If omitted, all rows in the table will be deleted. |
Example 1: Deleting all rows that meet the condition
DELETE FROM employees WHERE id = 10;
DELETE FROM employees WHERE id IN (SELECT id FROM temp_employees WHERE processed = 'Y');Example 2: Deleting all rows (proceed with caution)
DELETE FROM employees;Examples
sql
-- Delete a single row by primary key.
DELETE FROM employees WHERE id = 100;
-- Delete rows based on a range condition.
DELETE FROM employees WHERE salary < 30000;
-- Delete rows using a subquery.
DELETE FROM employees WHERE department_id IN (SELECT department_id FROM departments WHERE location = 'Old Office');