MySQL - Insert on Duplicate Key Update 语句
MySQL 中的 INSERT INTO 语句用于将新记录插入到特定表中。
MySQL Insert on Duplicate Key Update 语句
当我们尝试向具有唯一索引或主键的 MySQL 表列中插入新行时,如果插入的值在该列中已经存在,MySQL 将发出错误。发生这种情况是因为这些约束要求值唯一,并且不允许重复值。
但是,如果我们将 MySQL ON DUPLICATE KEY UPDATE 子句与 INSERT INTO 语句一起使用,MySQL 将使用新值更新现有行,而不是显示错误。
语法
以下是 MySQL 中 ON DUPLICATE KEY UPDATE 子句的基本语法 -
INSERT INTO my_table (col1, col2, ...) VALUES (val1, val2), (val3, val4), ... ON DUPLICATE KEY UPDATE <col1>=<val1>, <col2>=<val2>,...;
示例
首先,我们使用以下查询创建一个名为 CUSTOMERS 的表 -
CREATE TABLE CUSTOMERS ( ID int NOT NULL, NAME varchar(20) NOT NULL, AGE int NOT NULL, ADDRESS char (25), SALARY decimal (18, 2), PRIMARY KEY (ID) );
在这里,我们使用 INSERT INTO 语句将一些记录插入到上面创建的表中,如下所示 -
INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (1, 'Ramesh', 32, 'Ahmedabad', 2000.00 ), (2, 'Khilan', 25, 'Delhi', 1500.00 ), (3, 'Kaushik', 23, 'Kota', 2000.00 );
执行以下查询以显示上面创建的 CUSTOMERS 表中的记录 -
SELECT * FROM CUSTOMERS;
以下是 CUSTOMERS 表中的记录 -
ID | NAME | AGE | ADDRESS | SALARY |
---|---|---|---|---|
1 | Ramesh | 32 | Ahmedabad | 2000.00 |
2 | Khilan | 25 | Delhi | 1500.00 |
3 | Kaushik | 23 | Kota | 2000.00 |
此处,我们使用 INSERT INTO 语句向 CUSTOMERS 表中插入另一行,其 ID 值为 3 -
INSERT INTO CUSTOMERS (ID, NAME, AGE, ADDRESS, SALARY) VALUES (3, 'Chaitali', 25, 'Mumbai', 6500.00);
因此,MySQL 会报错,因为我们插入了重复的 ID 值 -
ERROR 1062 (23000): Duplicate entry '3' for key 'customers.PRIMARY'
我们可以避免上述错误,并使用 ON DUPLICATE KEY UPDATE 子句和 INSERT INTO 语句将新信息更新到现有行,如下所示 -
INSERT INTO CUSTOMERS (ID, NAME, AGE, ADDRESS, SALARY) VALUES (3, 'Chaitali', 25, 'Mumbai', 6500.00) ON DUPLICATE KEY UPDATE NAME = "Chaitali", AGE = 25, ADDRESS = "Mumbai", SALARY = 6500.00;
输出
从输出中可以看出,上述查询更新了 CUSTOMERS 表中的现有行。因此,它返回了两行受影响的行。
Query OK, 2 rows affected (0.01 sec)
验证
执行以下查询以验证现有行是否已使用新信息更新 -
SELECT * FROM CUSTOMERS;
我们观察表中的第三行,发现记录已更新。
ID | NAME | AGE | ADDRESS | SALARY |
---|---|---|---|---|
1 | Ramesh | 32 | Ahmedabad | 2000.00 |
2 | Khilan | 25 | Delhi | 1500.00 |
3 | Chaitali | 25 | Mumbai | 6500.00 |
示例
在下面的查询中,我们尝试使用 INSERT INTO 语句以及 ON DUPLICATE KEY UPDATE 子句向 CUSTOMERS 表中插入新行 -
INSERT INTO CUSTOMERS (ID, NAME, AGE, ADDRESS, SALARY) VALUES (4, 'Hardik', 27, 'Bhopal', 8500.00) ON DUPLICATE KEY UPDATE NAME = "Hardik", AGE = 27, ADDRESS = "Bhopal", SALARY = 8500.00;
输出
从输出中可以看出,插入新行时没有发生冲突。结果返回一行受影响的行。
Query OK, 1 row affected (0.01 sec)
验证
我们可以使用以下查询来验证新行是否已插入 CUSTOMERS 表中 -
SELECT * FROM CUSTOMERS;
如我们观察到的以下输出所示,新行已插入。
ID | NAME | AGE | ADDRESS | SALARY |
---|---|---|---|---|
1 | Ramesh | 32 | Ahmedabad | 2000.00 |
2 | Khilan | 25 | Delhi | 1500.00 |
3 | Chaitali | 25 | Mumbai | 6500.00 |
4 | Hardik | 27 | Bhopal | 8500.00 |
一次插入或更新多条记录
在 MySQL 中同时插入或更新多条记录时,每列的值可能会根据存在冲突的记录而有所不同。
例如,如果我们尝试插入四行新记录,但第三行的 ID 列与现有记录冲突,我们很可能希望根据您为第三行设想的数据来更新现有行。
示例
在执行下一个操作之前,让我们先查看一下已更新的 CUSTOMERS 表的记录 -
SELECT * FROM CUSTOMERS;
以下是更新后的 CUSTOMERS 表 -
ID | NAME | AGE | ADDRESS | SALARY |
---|---|---|---|---|
1 | Ramesh | 32 | Ahmedabad | 2000.00 |
2 | Khilan | 25 | Delhi | 1500.00 |
3 | Chaitali | 25 | Mumbai | 6500.00 |
4 | Hardik | 27 | Bhopal | 8500.00 |
以下查询在 CUSTOMERS 表中添加了两行新数据 -
INSERT INTO CUSTOMERS (ID, NAME, AGE, ADDRESS, SALARY) VALUES (5, "Komal", 22, "Hyderabad", 4500.00), (4, "Kaushik", 23, "Kota", 2000.00) ON DUPLICATE KEY UPDATE NAME = VALUES(NAME), AGE = VALUES(AGE), ADDRESS = VALUES(ADDRESS), SALARY = VALUES(SALARY);
输出
从输出中可以看出,新增了两行(ID 分别为 5 和 4),更新了一行(ID 4),但与现有行发生冲突(因为已有一行 ID 为"4")。
Query OK, 3 rows affected, 4 warnings (0.01 sec) Records: 2 Duplicates: 1 Warnings: 4
验证
执行以下查询,验证记录是否已插入 CUSTOMERS 表。
SELECT * FROM CUSTOMERS;
如果我们查看下面的"CUSTOMERS"表,我们可以看到按预期添加了两行新数据,并且冲突行的值已使用新信息进行了更新。
ID | NAME | AGE | ADDRESS | SALARY |
---|---|---|---|---|
1 | Ramesh | 32 | Ahmedabad | 2000.00 |
2 | Khilan | 25 | Delhi | 1500.00 |
3 | Chaitali | 25 | Mumbai | 6500.00 |
4 | Kaushik | 23 | Kota | 2000.00 |
5 | Komal | 22 | Hyderabad | 4500.00 |
客户端程序
除了使用 MySQL 查询在 MySQL 表中执行"插入重复键更新"查询外,我们还可以使用客户端程序在表上执行相同的操作。
语法
以下是此操作在各种编程语言中的语法 -
要通过 PHP 程序将 MySQL 表中的重复行更新为新行,我们使用 DUPLICATE KEY UPDATE 和 INSERT 语句,并使用 mysqli 函数 query() 作为 -
$sql = "INSERT INTO my_table (column1, column2, ...) VALUES (value1, value2), (value3, value4), ... ON DUPLICATE KEY UPDATE column1 = value1, column2 = value2, ..."; $mysqli->query($sql);
要通过 Node.js 程序将 MySQL 表中的重复行更新为新行,我们使用 DUPLICATE KEY UPDATE 和 INSERT 语句,并使用 mysql2 库中的 query() 函数 -
sql = "INSERT INTO my_table (column1, column2, ...) VALUES (value1, value2), (value3, value4), ... ON DUPLICATE KEY UPDATE column1 = value1, column2 = value2, ..."; con.query(sql);
要通过 Java 程序将 MySQL 表中的重复行更新为新行,我们使用 DUPLICATE KEY UPDATE 和 INSERT 语句,并使用 JDBC 函数 executeUpdate() 作为 -
String sql = "INSERT INTO my_table (column1, column2, ...) VALUES (value1, value2), (value3, value4), ... ON DUPLICATE KEY UPDATE column1 = value1, column2 = value2, ..."; statement.executeUpdate(sql);
要通过 Python 程序在 MySQL 平板电脑中将重复行更新为新行,我们使用 DUPLICATE KEY UPDATE 和 INSERT 语句,并使用 MySQL Connector/Python 的 execute() 函数执行 -
insert_on_duplicate_key_update_query = "INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...) ON DUPLICATE KEY UPDATE column1 = VALUES(column1), column2 = VALUES(column2), ..." cursorObj.execute(insert_on_duplicate_key_update_query)
示例
以下是程序 -
$dbhost = 'localhost'; $dbuser = 'root'; $dbpass = 'password'; $dbname = 'TUTORIALS'; $mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname); if($mysqli->connect_errno ) { printf("Connect failed: %s
", $mysqli->connect_error); exit(); } //printf('Connected successfully.
'); $q = "SELECT * FROM tutorials_tbl"; if($res = $mysqli->query($q)){ printf("Select query executed successfully..! "); printf("The table 'tutorials_tbl' records before insert into duplicate key update query executed: "); while($r = mysqli_fetch_array($res)){ print_r ($r); } } $sql = "INSERT INTO tutorials_tbl(tutorial_id, tutorial_title, tutorial_author, submission_date) VALUES(2, 'PHP Tut', 'unknown2', '2023-08-12') ON DUPLICATE KEY UPDATE tutorial_author = 'New Author'"; if($result = $mysqli->query($sql)){ printf("Insert on Duplicate Key Update query executed successfully..! "); } $q = "SELECT * FROM tutorials_tbl"; if($res = $mysqli->query($q)){ printf("Select query executed successfully..! "); printf("The table 'tutorials_tbl' records after insert into duplicate key update query executed: "); while($r = mysqli_fetch_array($res)){ print_r ($r); } } if($mysqli->error){ printf("Failed..!" , $mysqli->error); } $mysqli->close();
输出
获得的输出如下 -
Select query executed successfully..! The table 'tutorials_tbl' records before insert into duplicate key update query executed: Array ( [0] => 1 [tutorial_id] => 1 [1] => Java Tutorial [tutorial_title] => Java Tutorial [2] => new_author [tutorial_author] => new_author [3] => [submission_date] => ) Array ( [0] => 2 [tutorial_id] => 2 [1] => PHP Tut [tutorial_title] => PHP Tut [2] => unknown2 [tutorial_author] => unknown2 [3] => 2023-08-12 [submission_date] => 2023-08-12 ) Insert on Duplicate Key Update query executed successfully..! Select query executed successfully..! The table 'tutorials_tbl' records after insert into duplicate key update query executed: Array ( [0] => 1 [tutorial_id] => 1 [1] => Java Tutorial [tutorial_title] => Java Tutorial [2] => new_author [tutorial_author] => new_author [3] => [submission_date] => ) Array ( [0] => 2 [tutorial_id] => 2 [1] => PHP Tut [tutorial_title] => PHP Tut [2] => New Author [tutorial_author] => New Author [3] => 2023-08-12 [submission_date] => 2023-08-12 )
var mysql = require('mysql2'); var con = mysql.createConnection({ host: "localhost", user: "root", password: "Nr5a0204@123" }); //连接到 MySQL con.connect(function (err) { if (err) throw err; console.log("Connected!"); console.log("----------------------------------------"); //选择数据库 sql = "USE TUTORIALS" con.query(sql); //创建表 sql = "CREATE TABLE Actors (ID int auto_increment,NAME varchar(20) NOT NULL,LATEST_FILM varchar(20),Primary Key (ID));" con.query(sql); sql= "INSERT INTO Actors (NAME, LATEST_FILM)VALUES ('Prabhas', 'Salaar'),('Ram Charan', 'Game changer'),('Allu Arjun', 'Pushpa2');" con.query(sql, function (err, result) { if (err) throw err; console.log(result); console.log("----------------------------------------"); }); sql = "SELECT * FROM Actors;" con.query(sql, function (err, result) { if (err) throw err; console.log(result); console.log("----------------------------------------"); }); sql = "INSERT INTO Actors (ID, NAME) VALUES (3, 'Fahad') ON DUPLICATE KEY UPDATE NAME = 'Fahad';" con.query(sql, function (err, result) { if (err) throw err; console.log(result); console.log("----------------------------------------"); }); sql = "SELECT * FROM Actors;" con.query(sql, function (err, result) { if (err) throw err; console.log(result); }); });
输出
生成的输出如下 -
Connected! ---------------------------------------- ResultSetHeader { fieldCount: 0, affectedRows: 3, insertId: 1, info: 'Records: 3 Duplicates: 0 Warnings: 0', serverStatus: 2, warningStatus: 0, changedRows: 0 } ---------------------------------------- [ { ID: 1, NAME: 'Prabhas', LATEST_FILM: 'Salaar' }, { ID: 2, NAME: 'Ram Charan', LATEST_FILM: 'Game changer' }, { ID: 3, NAME: 'Allu Arjun', LATEST_FILM: 'Pushpa2' } ] ---------------------------------------- ResultSetHeader { fieldCount: 0, affectedRows: 2, insertId: 3, info: '', serverStatus: 2, warningStatus: 0, changedRows: 0 } ---------------------------------------- [ { ID: 1, NAME: 'Prabhas', LATEST_FILM: 'Salaar' }, { ID: 2, NAME: 'Ram Charan', LATEST_FILM: 'Game changer' }, { ID: 3, NAME: 'Fahad', LATEST_FILM: 'Pushpa2' } ]
public class InsertOnDuplicate { public static void main(String[] args) { String url = "jdbc:mysql://localhost:3306/TUTORIALS"; String user = "root"; String password = "password"; ResultSet rs; try { Class.forName("com.mysql.cj.jdbc.Driver"); Connection con = DriverManager.getConnection(url, user, password); Statement st = con.createStatement(); //System.out.println("Database connected successfully...!"); String sql = "SELECT * FROM Actors"; rs = st.executeQuery(sql); System.out.println("Table records before insert on duplicate key update: "); while(rs.next()) { String id = rs.getString("ID"); String name = rs.getString("NAME"); String latest_film = rs.getString("LATEST_FILM"); System.out.println("Id: " + id + ", Name: " + name + ", Latest_film: " + latest_film); } //让重复更新时使用插入 String sql1 = "INSERT INTO Actors (ID, NAME) VALUES (3, \"Ravi\") ON DUPLICATE KEY UPDATE NAME = \"Ravi\""; st.executeUpdate(sql1); System.out.println("Query insert on duplicate key update executed successfully....!"); String sql2 = "SELECT * FROM Actors"; rs = st.executeQuery(sql2); System.out.println("Table records after insert on duplicate update: "); while(rs.next()) { String id = rs.getString("ID"); String name = rs.getString("NAME"); String latest_film = rs.getString("LATEST_FILM"); System.out.println("Id: " + id + ", Name: " + name + ", Latest_film: " + latest_film); } }catch(Exception e) { e.printStackTrace(); } } }
输出
获得的输出如下所示 -
Table records before insert on duplicate key update: Id: 1, Name: Prabhas, Latest_film: Salaar Id: 2, Name: Ram Charan, Latest_film: Game changer Id: 3, Name: Allu Arjun, Latest_film: Pushpa2 Query insert on duplicate key update executed successfully....! Table records after insert on duplicate update: Id: 1, Name: Prabhas, Latest_film: Salaar Id: 2, Name: Ram Charan, Latest_film: Game changer Id: 3, Name: Ravi, Latest_film: Pushpa2
import mysql.connector #建立连接 connection = mysql.connector.connect( host='localhost', user='root', password='password', database='tut' ) cursorObj = connection.cursor() insert_on_duplicate_key_update = "INSERT INTO tutorials_tbl (tutorial_id, tutorial_title, tutorial_author, submission_date) VALUES (7, 'New Tutorial', 'John Doe', '2023-07-25') ON DUPLICATE KEY UPDATE tutorial_title='Updated Tutorial', tutorial_author='Jane Smith', submission_date='2023-07-28'" cursorObj.execute(insert_on_duplicate_key_update) connection.commit() print("INSERT on duplicate key update query executed successfully.") cursorObj.close() connection.close()
输出
以下是上述代码的输出 -
INSERT on duplicate key update query executed successfully.