用sql语句写增删改查

增加数据：

INSERT INTO table_name (column1, column2, column3, ...)
VALUES (value1, value2, value3, ...);

删除数据：

DELETE FROM table_name
WHERE some_column = some_value;

更新数据：

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE some_column = some_value;

查询数据：

SELECT column1, column2, ...
FROM table_name
WHERE some_column = some_value;

相关问题

SQL语句进行增删改查

SQL语句是结构化查询语言的简称，是用于管理关系数据库系统中数据的语言。以下是SQL语句进行增删改查的示例：

1. 增加数据：

INSERT INTO table_name (column1, column2, column3, ...)
VALUES (value1, value2, value3, ...);

例如：

INSERT INTO customers (name, email, phone)
VALUES ('John Doe', 'johndoe@email.com', '123456789');

2. 删除数据：

DELETE FROM table_name
WHERE some_column = some_value;

例如：

DELETE FROM customers
WHERE id = 1;

3. 修改数据：

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE some_column = some_value;

例如：

UPDATE customers
SET name = 'Jane Doe', email = 'janedoe@email.com'
WHERE id = 2;

4. 查询数据：

SELECT column1, column2, ...
FROM table_name
WHERE some_column = some_value;

例如：

SELECT name, email, phone
FROM customers
WHERE id = 2;

用Java写增删改查的SQL语句

当你使用Java编写增删改查（CRUD）的SQL语句时，可以使用Java的JDBC（Java Database Connectivity）来与数据库进行交互。以下是一个示例，展示了如何使用Java编写增删改查的SQL语句：

1. 增加（INSERT）数据：

String insertQuery = "INSERT INTO tableName (column1, column2) VALUES (?, ?)";

try (Connection connection = DriverManager.getConnection(url, username, password);
     PreparedStatement statement = connection.prepareStatement(insertQuery)) {

    statement.setString(1, value1); // 设置第一个参数的值
    statement.setString(2, value2); // 设置第二个参数的值

    int rowsInserted = statement.executeUpdate();
    if (rowsInserted > 0) {
        System.out.println("数据插入成功！");
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

2. 删除（DELETE）数据：

String deleteQuery = "DELETE FROM tableName WHERE condition";

try (Connection connection = DriverManager.getConnection(url, username, password);
     Statement statement = connection.createStatement()) {

    int rowsDeleted = statement.executeUpdate(deleteQuery);
    if (rowsDeleted > 0) {
        System.out.println("数据删除成功！");
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

3. 更新（UPDATE）数据：

String updateQuery = "UPDATE tableName SET column1 = ?, column2 = ? WHERE condition";

try (Connection connection = DriverManager.getConnection(url, username, password);
     PreparedStatement statement = connection.prepareStatement(updateQuery)) {

    statement.setString(1, newValue1); // 设置新的第一个参数的值
    statement.setString(2, newValue2); // 设置新的第二个参数的值

    int rowsUpdated = statement.executeUpdate();
    if (rowsUpdated > 0) {
        System.out.println("数据更新成功！");
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

4. 查询（SELECT）数据：

String selectQuery = "SELECT column1, column2 FROM tableName WHERE condition";

try (Connection connection = DriverManager.getConnection(url, username, password);
     Statement statement = connection.createStatement();
     ResultSet resultSet = statement.executeQuery(selectQuery)) {

    while (resultSet.next()) {
        String value1 = resultSet.getString("column1"); // 获取第一个列的值
        String value2 = resultSet.getString("column2"); // 获取第二个列的值

        System.out.println("value1: " + value1 + ", value2: " + value2);
    }
} catch (SQLException ex) {
    ex.printStackTrace();
}

请注意，上述示例中的"tableName"、"column1"、"column2"和"condition"应替换为实际的表名、列名和条件。此外，你还需要提供数据库的URL、用户名和密码。