Khóa học miễn phí MySQL – Insert Ignore nhận dự án làm có lương

MySQL – Insert Ignore

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In MySQL, the INSERT INTO statement can be used to insert one or more records into a table.

In some scenarios, if a particular column has a UNIQUE constraint and if we are trying to add duplicates records into that particular column using the INSERT INTO statement, MySQL will terminate the statement and returns an error. As the result, no rows are inserted into the table.

MySQL Insert Ignore Statement

However, if we use the MySQL INSERT IGNORE INTO statement, it will not display an error. Instead, it allows us to insert valid data into a table and ignores the rows with invalid data that would cause errors.

Following are some scenarios where the INSERT IGNORE INTO statement avoid errors:

  • When we insert a duplicate value in the column of a table that has UNIQUE key or PRIMARY key constraints.
  • When we try to add NULL values to a column where it has NOT NULL constraint on it.

Syntax

Following is the syntax of the INSERT IGNORE statement in MySQL −

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

Example

First of all, let us create a table named CUSTOMERS using the following query below −

Note: The UNIQUE constraint ensures that no duplicate value can be stored or inserted in the NAME column.

CREATE TABLE CUSTOMERS (
   ID int NOT NULL,
   NAME varchar(20) NOT NULL UNIQUE,
   PRIMARY KEY (ID)
);

The following query inserts three records into the CUSTOMERS table −

INSERT INTO CUSTOMERS (ID, NAME) 
VALUES (1, "Ajay"), (2, "Vinay"), (3, "Arjun");

Execute the following query to display the records present in the CUSTOMERS table −

SELECT * FROM CUSTOMERS;

Following are the records of CUSTOMERS table −

ID NAME
1 Ajay
2 Arjun
3 Vinay

Now, let us insert a duplicate record into the NAME column of CUSTOMERS table using the below query −

INSERT INTO CUSTOMERS (NAME) VALUES (2, "Arjun");

It returns an error because the NAME “Arjun” is already present in the column and hence it violates the UNIQUE constraint.

ERROR 1062 (23000): Duplicate entry ''Arjun'' for key ''customers.NAME''

Now, let us use the INSERT IGNORE statement as shown below −

INSERT IGNORE INTO CUSTOMERS (NAME) VALUES (2, "Arjun");

Output

Though we are inserting a duplicate value, it do not display any error, instead it gives a warning.

Query OK, 0 rows affected, 1 warning (0.00 sec)

We can find the details of the above warning using the following query −

SHOW WARNINGS;

Following is the warnings table −

Level Code Message
Warning 1062 Duplicate entry ”Arjun” for key ”customers.NAME”

Verification

If we try to verify the CUSTOMERS table, we can find that the duplicate row which we tried to insert will not be present in the table.

SELECT * FROM CUSTOMERS;

The output for the program above is produced as given below −

ID NAME
1 Ajay
2 Arjun
3 Vinay

MySQL INSERT IGNORE and STRICT mode

The strict mode controls how MySQL handles the invalid, missing, or out of range values that are going to be added into a table through data-change statements such as INSERT or UPDATE.

So, if the strict mode is ON, and we are trying to insert some invalid values into a table using the INSERT statement, MySQL terminates the statement returns an error message.

However, if we use the INSERT IGNORE INTO statement, instead of returning an error, MySQL will adjust those values to make them valid before adding the value to the table.

Example

Let us create a table named CUSTOMERS using the following query −

Note: The NAME column accepts only strings whose length is less than or equal to five.

CREATE TABLE CUSTOMERS (
   ID int NOT NULL,
   NAME varchar(5),
   PRIMARY KEY (ID)
);

Here, we are trying to insert a value into NAME column whose length is greater than 5.

INSERT INTO CUSTOMERS (NAME) VALUES (1, "Malinga");

It returns an error as shown below −

ERROR 1406 (22001): Data too long for column ''NAME'' at row 1

Now, we are trying to use the INSERT IGNORE statement to insert the same string −

INSERT IGNORE INTO CUSTOMERS (NAME) VALUES (1, "Malinga");

Output

As we can see in the output, instead of returning an error, it displays an warning −

Query OK, 1 row affected, 1 warning (0.01 sec)

Let us find the details of the above warning using the following command −

SHOW WARNINGS;

As we can see in the output below, MySQL truncated the data before inserting it into the CUSTOMERS table.

Level Code Message
Warning 1265 Data truncated for column ”NAME” at row 1

Verification

Execute the following query to verify the records of the CUSTOMERS table −

Select * from CUSTOMERS;

As we can see in the CUSTOMERS table below, the value has been truncated to 5 characters and inserted into the table.

ID NAME
1 Malin

Insert Ignore Query Using a Client Program

Besides using MySQL queries to perform the Insert Ignore operation, we can also use client programs like Node.js, PHP, Java, and Python to achieve the same result.

Syntax

Following are the syntaxes of this operation in various programming languages −

To to insert valid data into a MySQL table through a PHP program, we use the ”IGNORE” along with ”INSERT INTO” statement using the mysqli function query() as follows −

$sql = "INSERT IGNORE INTO table_name (column1, column2, column3, ...) 
VALUES (value1, value2, value3, ...)"; 
$mysqli->query($sql);

To to insert valid data into a MySQL table through a Node.js program, we use the ”IGNORE” along with ”INSERT INTO” statement using the query() function of the mysql2 library as follows −

sql = "INSERT IGNORE INTO table_name (column1, column2, column3, ...)
VALUES (value1, value2, value3, ...)";
con.query(sql);

To to insert valid data into a MySQL table through a Java program, we use the ”IGNORE” along with ”INSERT INTO” statement using the JDBC function executeUpdate() as follows −

String sql = "INSERT IGNORE INTO table_name (column1, column2, column3, ...) 
VALUES (value1, value2, value3, ...)";
statement.executeUpdate(sql);

To to insert valid data into a MySQL table through a Python program, we use the ”IGNORE” along with ”INSERT INTO” statement using the execute() function of the MySQL Connector/Python as follows −

insert_ignore_query = "INSERT IGNORE INTO table_name (column1, column2, ...) 
VALUES (value1, value2, ...)"
cursorObj.execute(insert_ignore_query)

Example

Following are the programs −

$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.
''); $sql = "INSERT IGNORE INTO tutorials_tbl values(5, ''Java Tutorial'', ''newauther3'', ''2022-11-15'')"; if($result = $mysqli->query($sql)){ printf("Data inserted successfully..!"); } $q = "SELECT * FROM tutorials_tbl where tutorial_id = 5"; if($res = $mysqli->query($q)){ printf("Records after insert ignore statement: "); while($row = mysqli_fetch_row($res)){ print_r ($row); } } if($mysqli->error){ printf("Failed..!" , $mysqli->error); } $mysqli->close();

Output

The output obtained is as follows −

Data inserted successfully..!Records after insert ignore statement: Array
(
  [0] => 5
  [1] => Java Tutorial
  [2] => newauther3
  [3] => 2022-11-15
)
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!");

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

  //Creating Table
  sql = "CREATE TABLE STUDENTS (ID int AUTO_INCREMENT,NAME varchar(5) NOT NULL UNIQUE,PRIMARY KEY (ID));"
  con.query(sql);

  sql = "INSERT INTO STUDENTS (NAME) VALUES (''Ajay''), (''Vinay''), (''Arjun'');"
  con.query(sql);

  sql= "INSERT IGNORE INTO STUDENTS (NAME) VALUES (''Arjun'');"
  con.query(sql, function (err, result) {
      if (err) throw err;
      console.log(result);
      console.log("----------------------------------------");
  });

  sql = "SHOW WARNINGS;"
  con.query(sql, function (err, result) {
    if (err) throw err;
    console.log(result);
    console.log("----------------------------------------");
  });

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

Output

The output produced is as follows −

Connected!
ResultSetHeader {
  fieldCount: 0,
  affectedRows: 0,
  insertId: 0,
  info: '''',
  serverStatus: 2,
  warningStatus: 1,
  changedRows: 0
}
----------------------------------------
[
  {
    Level: ''Warning'',
    Code: 1062,
    Message: "Duplicate entry ''Arjun'' for key ''students.NAME''"
  }
]
----------------------------------------
[
  { ID: 1, NAME: ''Ajay'' },
  { ID: 3, NAME: ''Arjun'' },
  { ID: 2, NAME: ''Vinay'' }
]  
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class InsertIgnore {
  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 STUDENTS";
            rs = st.executeQuery(sql);
            System.out.println("Table records before insert ignore: ");
            while(rs.next()) {
              String Id = rs.getString("Id");
              String Name = rs.getString("Name");
              System.out.println("Id: " + Id + ", Name: " + Name);
            }
            String sql1 = "INSERT INTO STUDENTS (NAME) VALUES ("Arjun")";
            st.executeUpdate(sql1);
            System.out.println("Record with name ''Arjun'' inserted successfully...!");
            String sql2 = "SELECT * FROM STUDENTS";
            rs = st.executeQuery(sql2);
            System.out.println("Table record after insert: ");
            while(rs.next()) {
              String Id = rs.getString("Id");
              String Name = rs.getString("Name");
              System.out.println("Id: " + Id + ", Name: " + Name);
            }
            //now let use insert ignore query to insert a duplicate records into the Students table
            String sql3 = "INSERT IGNORE INTO STUDENTS (NAME) VALUES ("Arjun")";
            st.executeUpdate(sql3);
            System.out.println("Insert ignore query executed successfully....!");
            String sql4 = "SELECT * FROM STUDENTS";
            rs = st.executeQuery(sql4);
            System.out.println("Table records after insert ingore: ");
            while(rs.next()) {
              String Id = rs.getString("Id");
              String Name = rs.getString("Name");
              System.out.println("Id: " + Id + ", Name: " + Name);
            }
    }catch(Exception e) {
      e.printStackTrace();
    }
  }
}                                 

Output

The output obtained is as shown below −

Table records before insert ignore: 
Id: 1, Name: Ajay
Id: 2, Name: Vinay
Record with name ''Arjun'' inserted successfully...!
Table record after insert: 
Id: 1, Name: Ajay
Id: 9, Name: Arjun
Id: 2, Name: Vinay
Insert ignore query executed successfully....!
Table records after insert ingore: 
Id: 1, Name: Ajay
Id: 9, Name: Arjun
Id: 2, Name: Vinay       
import mysql.connector
#establishing the connection
connection = mysql.connector.connect(
    host=''localhost'',
    user=''root'',
    password=''password'',
    database=''tut''
)
cursorObj = connection.cursor()
insert_ignore_query = "INSERT IGNORE INTO tutorials_tbl (tutorial_id, tutorial_title, tutorial_author, submission_date) VALUES (7, ''New Tutorial'', ''John Doe'', ''2023-07-25'')"
cursorObj.execute(insert_ignore_query)
connection.commit()
print("INSERT IGNORE query executed successfully.")
cursorObj.close()
connection.close()                                      

Output

Following is the output of the above code −

INSERT IGNORE query executed successfully.

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