DELETE 語句用于刪除表中的記錄。
SQL DELETE 語句
DELETE 語句用于刪除表中的行。
SQL DELETE 語法
DELETE FROM table_name
WHERE some_column=some_value;
WHERE some_column=some_value;
![]() | 請注意 SQL DELETE 語句中的 WHERE 子句! WHERE 子句規定哪條記錄或者哪些記錄需要刪除。如果您省略了 WHERE 子句,所有的記錄都將被刪除! |
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演示數據庫
在本教程中,我們將使用眾所周知的 Northwind 樣本數據庫。
下面是選自 "Customers" 表的數據:
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 snabbk?p | Christina Berglund | Berguvsv?gen 8 | Lule? | S-958 22 | Sweden |
SQL DELETE 實例
假設我們要從 "Customers" 表中刪除客戶 "Alfreds Futterkiste"。
我們使用下面的 SQL 語句:
實例
DELETE FROM Customers
WHERE CustomerName='Alfreds Futterkiste' AND ContactName='Maria Anders';
WHERE CustomerName='Alfreds Futterkiste' AND ContactName='Maria Anders';
現在,"Customers" 表如下所示:
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 snabbk?p | Christina Berglund | Berguvsv?gen 8 | Lule? | S-958 22 | Sweden |
刪除所有數據
您可以在不刪除表的情況下,刪除表中所有的行。這意味著表結構、屬性、索引將保持不變:
DELETE FROM table_name;
or
DELETE * FROM table_name;
or
DELETE * FROM table_name;
注釋:在刪除記錄時要格外小心!因為您不能重來!