ORACLE_DELETE
SQL DELETE Statement
The SQL DELETE Statement
The DELETE statement is used to delete existing records in a table.
DELETE Syntax
WHERE condition;
Note: Be careful when deleting records in a table! Notice the WHERE clause in the DELETE statement. The WHERE clause specifies which record(s) that should be deleted. If you omit the WHERE clause, all records in the table will be deleted!
Demo Database
Below is a selection from the "Customers" table in the Northwind sample database:
CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
---|---|---|---|---|---|---|
1 | Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |
SQL DELETE Example
The following SQL statement deletes the customer "Alfreds Futterkiste" from the "Customers" table:
Example
WHERE CustomerName='Alfreds Futterkiste';
The "Customers" table will now look like this:
CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
---|---|---|---|---|---|---|
2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |
Delete All Records
It is possible to delete all rows in a table without deleting the table. This means that the table structure, attributes, and indexes will be intact:
or:
Delete All Null Records
delete * from emp where comm is null;
delect * from emp where comm='';
CREATE OR REPLACE PROCEDURE emp01_delete_null AS
BEGIN
DELETE FROM emp01 WHERE comm IS NULL;
COMMIT;
END emp01_delete_null; execute emp01_delete_null;
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