MySQL - 插入資料到選擇結果



MySQL Insert Into Select 語句

在 MySQL 中,**INSERT INTO... SELECT** 語句用於將一個或多個行從現有表新增到目標表。

此語句是兩個不同語句的組合:INSERT INTO 和 SELECT。

  • MySQL INSERT INTO 語句是資料庫管理中常用的命令,它只需要表名和要插入表中的值。但是,務必確保插入的資料與表列的結構和資料型別匹配。
  • SELECT 語句用於從現有的資料庫表中獲取資料。

當上述語句一起使用時,SELECT 語句首先從現有表中獲取資料,然後**INSERT INTO** 語句將檢索到的資料插入到另一個表(如果它們具有相同的表結構)。

語法

以下是使用 insert into select 語句的語法:

INSERT INTO table2 (column1, column2, column3, ...)
SELECT column1, column2, column3, ... 
FROM table1
WHERE condition;

在執行以下查詢之前,我們必須考慮以下一些重要事項:

  • 在我們即將插入資料的資料庫中,必須已經存在一個表。
  • 源表和目標表都必須匹配其結構。

示例

首先,讓我們使用以下查詢建立一個名為**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)
);

以下查詢將 7 條記錄插入到上面建立的表中:

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 ),
(4, 'Chaitali', 25, 'Mumbai', 6500.00 ),
(5, 'Hardik', 27, 'Bhopal', 8500.00 ),
(6, 'Komal', 22, 'Hyderabad', 4500.00 ),
(7, 'Muffy', 24, 'Indore', 10000.00 );

執行以下查詢以檢索 CUSTOMERS 表中的所有記錄:

Select * From CUSTOMERS;

以下是 CUSTOMERS 表:

ID NAME AGE ADDRESS SALARY
1 Ramesh 32 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
3 Kaushik 23 Kota 2000.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

將所需資料從一個表插入到另一個表

我們可能會遇到一些情況,我們只想將少量記錄新增到另一個表中。這可以透過使用 WHERE 子句選擇查詢返回的所有行數來實現。

示例

在此之前,讓我們再建立一個名為**CUSTOMERS_copy**的表,其結構與之前建立的 CUSTOMERS 表類似:

CREATE TABLE CUSTOMERS_copy (
   ID INT AUTO_INCREMENT,
   NAME VARCHAR(20) NOT NULL,
   AGE INT NOT NULL,
   ADDRESS CHAR (25),
   SALARY DECIMAL (18, 2),
   PRIMARY KEY (ID)
);

在以下查詢中,我們嘗試從 CUSTOMERS 表中獲取記錄並將其插入到 CUSTOMERS_copy 表中。

INSERT INTO CUSTOMERS_copy (ID, NAME, AGE, ADDRESS, SALARY)
SELECT ID, NAME, AGE, ADDRESS, SALARY FROM CUSTOMERS
WHERE AGE >= 25;

輸出

上面程式的輸出如下所示:

Query OK, 4 rows affected (0.01 sec)
Records: 4  Duplicates: 0  Warnings: 0	

驗證

要確認年齡在 25 歲或以上來自“CUSTOMERS”表的記錄是否已插入到目標表“CUSTOMERS_copy”中,請執行以下查詢:

SELECT * FROM CUSTOMERS_copy;

以下是年齡在 25 歲或以上的記錄:

ID NAME AGE ADDRESS SALARY
1 Ramesh 32 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00

使用 LIMIT 插入行

使用 MySQL LIMIT 子句,我們可以指定應新增到目標表的查詢行數。

示例

在繼續之前,讓我們首先使用以下查詢截斷**CUSTOMERS_copy**表中的所有行:

TRUNCATE TABLE CUSTOMERS_copy;

現在,我們將使用 LIMIT 子句插入 CUSTOMERS 表中按 AGE 排序的前 3 條記錄:

INSERT INTO CUSTOMERS_copy (ID, NAME, AGE, ADDRESS, SALARY)
SELECT ID, NAME, AGE, ADDRESS, SALARY FROM CUSTOMERS
ORDER BY AGE LIMIT 3;

輸出

上面程式的輸出如下所示:

Query OK, 3 rows affected (0.01 sec)
Records: 3  Duplicates: 0  Warnings: 0

驗證

執行以下查詢以驗證記錄是否反映在 CUSTOMERS_copy 表中:

SELECT * FROM CUSTOMERS_copy;

以下是這些記錄:

ID NAME AGE ADDRESS SALARY
3 Kaushik 23 Kota 2000.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

將一個表的所有列插入到另一個表

我們還可以將一個表中的每一列插入到另一個表中。為此,以下是語法:

INSERT INTO table2
SELECT * FROM table1

在插入所有記錄之前,首先使用以下語句截斷 CUSTOMERS_copy 表中的所有行:

TRUNCATE TABLE CUSTOMERS_copy;

在下面的查詢中,我們嘗試將 CUSTOMERS 表中的所有列新增到 CUSTOMERS_copy 表中:

INSERT INTO CUSTOMERS_copy SELECT * FROM CUSTOMERS;

輸出

所有列已插入,沒有錯誤。

Query OK, 7 rows affected (0.01 sec)
Records: 7  Duplicates: 0  Warnings: 0

驗證

我們可以使用 SELECT 語句檢索其內容來驗證更改是否反映在 CUSTOMERS_copy 表中。

SELECT * FROM CUSTOMERS_copy;

以下是 CUSTOMERS_copy 表:

ID NAME AGE ADDRESS SALARY
1 Ramesh 32 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
3 Kaushik 23 Kota 2000.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

使用客戶端程式進行 INSERT INTO SELECT

除了使用 MySQL 查詢執行 INSERT INTO ... SELECT 語句之外,我們還可以使用 Node.js、PHP、Java 和 Python 等客戶端程式來實現相同的結果。

語法

以下是各種程式語言中此操作的語法:

要透過 PHP 程式將資料從一個 MySQL 表插入到另一個 MySQL 表中,我們需要使用 **mysqli** 函式 **query()** 執行“INSERT INTO SELECT”語句,如下所示:

$sql = "INSERT INTO new_tutorials_tbl SELECT * FROM tutorials_tbl WHERE tutorial_id = 2";
$mysqli->query($sql);

要透過 Node.js 程式將資料從一個 MySQL 表插入到另一個 MySQL 表中,我們需要使用 **mysql2** 庫的 **query()** 函式執行“INSERT INTO SELECT”語句,如下所示:

sql = "INSERT INTO Agentdemo(ID, NAME, GENDER, AGE) SELECT ID, NAME, GENDER, AGE FROM Agent WHERE GENDER = 'Male'";
con.query(sql);  

要透過 Java 程式將資料從一個 MySQL 表插入到另一個 MySQL 表中,我們需要使用 **JDBC** 函式 **executeUpdate()** 執行“INSERT INTO SELECT”語句,如下所示:

String sql = "INSERT INTO Agentdemo(ID, NAME, GENDER, AGE) SELECT ID, NAME, GENDER, AGE FROM Agent WHERE GENDER = \"Male\"";
st.executeUpdate(sql);

要透過 Python 程式將資料從一個 MySQL 表插入到另一個 MySQL 表中,我們需要使用 MySQL **Connector/Python** 的 **execute()** 函式執行“INSERT INTO SELECT”語句,如下所示:

sql = "INSERT INTO new_tutorials_tbl 
(tutorial_id, tutorial_title, tutorial_author, submission_date) 
SELECT tutorial_id, tutorial_title, tutorial_author, submission_date FROM tutorials_tbl"
insert_into_select_query = sql
cursorObj.execute(insert_into_select_query)

示例

以下是程式:

$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.
'); $q = "SELECT * FROM new_tutorials_tbl"; if($res = $mysqli->query($q)){ printf("Select query executed successfully..!\n"); printf("The table 'new_tutorials_tbl' records before insert into select query: \n"); while($r = mysqli_fetch_array($res)){ print_r ($r); } } $sql = "INSERT INTO new_tutorials_tbl SELECT * FROM tutorials_tbl WHERE tutorial_id = 2"; if($result = $mysqli->query($sql)){ printf("Insert into select query executed successfully..! \n"); } $q = "SELECT * FROM new_tutorials_tbl"; if($res = $mysqli->query($q)){ printf("Select query executed successfully..!\n"); printf("The table 'new_tutorials_tbl' records after insert into select query: \n"); while($r = mysqli_fetch_array($res)){ print_r ($r); } } if($mysqli->error){ printf("Failed..!" , $mysqli->error); } $mysqli->close();

輸出

獲得的輸出如下:

Select query executed successfully..!
The table 'new_tutorials_tbl' records before insert into select query:
Array
(
    [0] => 1
    [tutorial_id] => 1
    [1] => Java Tutorial
    [tutorial_title] => Java Tutorial
    [2] => new_author
    [tutorial_author] => new_author
    [3] =>
    [submission_date] =>
)
Insert into select query executed successfully..!
Select query executed successfully..!
The table 'new_tutorials_tbl' records after insert into select query:
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
)  
var mysql = require('mysql2');
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "Nr5a0204@123"
});

  //Connecting to MySQL
  con.connect(function (err) {
  if (err) throw err;
  console.log("Connected!");
  console.log("----------------------------------------");

  //Selecting a Database
  sql = "USE TUTORIALS"
  con.query(sql);

  sql = "CREATE TABLE Agent (ID int NOT NULL,NAME varchar(20) NOT NULL,GENDER varchar(20) NOT NULL,AGE int NOT NULL,PRIMARY KEY(ID));"
  con.query(sql);

  sql = "INSERT INTO Agent VALUES (1,'Msd', 'Male', 21), (2,'Virat', 'Male', 23), (3,'Perry', 'Female', 24), (4,'Smiti', 'Female', 18), (5,'Rose', 'Female', 23);"
  con.query(sql);

  sql = "SELECT * FROM Agent;"
  con.query(sql, function (err, result) {
    if (err) throw err;
    console.log(result);
    console.log("-------------------------------------------------------");
  });

  sql = "CREATE TABLE Agentdemo(ID int NOT NULL,NAME varchar(50) NOT NULL,GENDER varchar(20) NOT NULL,AGE int NOT NULL,PRIMARY KEY(ID));"
  con.query(sql);

  //Inserting required data from one table to another 
  sql = "INSERT INTO Agentdemo(ID, NAME, GENDER, AGE) SELECT ID, NAME, GENDER, AGE FROM Agent WHERE GENDER = 'Male'";
  con.query(sql);

  sql = "SELECT * FROM Agentdemo;"
  con.query(sql, function (err, result) {
    if (err) throw err;
    console.log(result);
  });
});        

輸出

產生的輸出如下:

Connected!
----------------------------------------
[
  { ID: 1, NAME: 'Msd', GENDER: 'Male', AGE: 21 },
  { ID: 2, NAME: 'Virat', GENDER: 'Male', AGE: 23 },
  { ID: 3, NAME: 'Perry', GENDER: 'Female', AGE: 24 },
  { ID: 4, NAME: 'Smiti', GENDER: 'Female', AGE: 18 },
  { ID: 5, NAME: 'Rose', GENDER: 'Female', AGE: 23 }
]
-------------------------------------------------------
[
  { ID: 1, NAME: 'Msd', GENDER: 'Male', AGE: 21 },
  { ID: 2, NAME: 'Virat', GENDER: 'Male', AGE: 23 }
]
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class InsertIntoSelect {
  public static void main(String[] args) {
    String url = "jdbc:mysql://: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 Agent";
            rs = st.executeQuery(sql);
            System.out.println("Agent table records: ");
            while(rs.next()) {
              String id = rs.getString("Id");
              String name = rs.getString("Name");
              String gender = rs.getString("Gender");
              String age = rs.getString("Age");
              System.out.println("Id: " + id + ", Name: " + name + "Gender: " + gender + ", Age: " + age);
            }
            String sql1 = "SELECT * FROM Agentdemo";
            rs = st.executeQuery(sql1);
            System.out.println("Agentdemo table before after insert into select: ");
            while(rs.next()) {
              String id = rs.getString("Id");
              String name = rs.getString("Name");
              String gender = rs.getString("Gender");
              String age = rs.getString("Age");
              System.out.println("Id: " + id + ", Name: " + name + "Gender: " + gender + ", Age: " + age);
            }
            //now let use the insert into select query
            String sql2 = "INSERT INTO Agentdemo(ID, NAME, GENDER, AGE) SELECT ID, NAME, GENDER, AGE FROM Agent WHERE GENDER = \"Male\"";
            st.executeUpdate(sql2);
            String sql3 = "SELECT * FROM Agentdemo";
            rs = st.executeQuery(sql3);
            System.out.println("Agentdemo table after after insert into select: ");
            while(rs.next()) {
              String id = rs.getString("Id");
              String name = rs.getString("Name");
              String gender = rs.getString("Gender");
              String age = rs.getString("Age");
              System.out.println("Id: " + id + ", Name: " + name + "Gender: " + gender + ", Age: " + age);
            }
    }catch(Exception e) {
      e.printStackTrace();
    }
  }
}        

輸出

獲得的輸出如下所示:

Agent table records: 
Id: 1, Name: MsdGender: Male, Age: 21
Id: 2, Name: ViratGender: Male, Age: 23
Id: 3, Name: PerryGender: Female, Age: 24
Id: 4, Name: SmitiGender: Female, Age: 18
Id: 5, Name: RoseGender: Female, Age: 23
Agentdemo table before after insert into select: 
Agentdemo table after after insert into select: 
Id: 1, Name: MsdGender: Male, Age: 21
Id: 2, Name: ViratGender: Male, Age: 23
import mysql.connector
#establishing the connection
connection = mysql.connector.connect(
    host='localhost',
    user='root',
    password='password',
    database='tut'
)
cursorObj = connection.cursor()
insert_into_select_query = "INSERT INTO new_tutorials_tbl (tutorial_id, tutorial_title, tutorial_author, submission_date) SELECT tutorial_id, tutorial_title, tutorial_author, submission_date FROM tutorials_tbl"
cursorObj.execute(insert_into_select_query)
connection.commit()
print("Data inserted into new table successfully.")
cursorObj.close()
connection.close()        

輸出

以下是上述程式碼的輸出:

Data inserted into new table successfully.
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