如果不存在，则将多个值插入表 MySQL

Question

I have a table with 3 columns (ID, username, full name), I want the ID to be AUTOINCREMENT. I want to insert into the table only if it does not already exist in the table.

This is my Code:

$fullName = $_POST['fullname'];
$username = $_POST['username'];
$dbhost = "localhost";
  $dbname = "databasename";
  $dbusername = "root";
  $dbpassword = "";

  $link = new PDO("mysql:host=$dbhost;dbname=$dbname","$dbusername","");

  $statement = $link->prepare('INSERT INTO accounts (username, fullname)
      VALUES (:username, :fname)');

  $statement->execute([
      'fname' => $fullName,
      'username' => $usernameget,
  ]);

Answer 1

If your id is already autoncrement then you no need to mention in query.

You can simply write below query

insert into accounts (username,fullname) values( $username , $fullname )

Answer 2

There's several things to fix here.

• Don't specify column values if you don't need to, or don't care about the value. Only specify if necessary or relevant. In this case id should be omitted.
• Always use placeholder values for your user data. Never put $_GET or $_POST data directly in a query.
• To avoid duplication add a UNIQUE constraint on the table.

To fix that you do adjust your code:

// Enable exceptions, avoiding the need for manual error checking
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

// Try and keep the order of things like this consistent through your code
$username = $_POST['username'];
$fullname = $_POST['fullname'];

// Here using a short, common name for the database handle $db    
$db = new mysqli("localhost","root","","database");

// Prepare your insert first as a query with no data, only placeholders
$db->prepare("insert into accounts (username,fullname) values(?,?)");

// Bind the data to the placeholders, here two string ("s") values.
$db->bind_param('ss', $username, $fullname);

// Execute the query
$db->execute();

To add the UNIQUE constraints useCREATE INDEX :

CREATE INDEX idx_accounts_username (username);
CREATE INDEX idx_accounts_full_name (full_name);

That has to be run in your MySQL shell, not PHP.

When a UNIQUE constraint is in place MySQL will not allow duplicate data. Note that NULL values don't count, and can be "duplicated". Set NOT NULL on your columns to force them to be completely unique.

Answer 3

由于您的id是自动增量主键，因此您可以使用以下命令创建或更新它：

insert into accounts (username,fullname) values( $username , $fullname ) on duplicate key update username = '$username',fullname = '$fullname'

Answer 4

you can do this with if else condition in PHP

$fullname = $_POST['fullname'];
$username = $_POST['username'];

$chk = mysqli_query("select * FROM `accounts` where fullname='$fullname' and username='$username'");
$rs = mysqli_fetch_array($chk);
if($rs == "")
{
    $ins = mysqli_query("INSERT INTO `accounts`(fullname,username) VALUES ('$fullname','$username'))";
} 
else{
    echo "Duplicate entry";
}   

---

or you can do this by SQL Query also.

INSERT INTO accounts(username,fullname)
SELECT * from (SELECT '$username', '$fullname') AS tmp
WHERE NOT EXISTS
(SELECT username FROM accounts WHERE username='$username')

Answer 5

To get correct answers, a question must be asked with as much explanation as possible. you should atleast tell what have you done and then what are you getting.
As far as i have understood, to achieve your goal, the table structure must be changed and inserting query also.
Remember to accept the answer and click the upvote button if the answer satisfies you,
else give more information in the question, so that members here, can give right answers.

If you understand table creating queries go to bottom of this answer or else do as follows:
if you use gui to create table,
1. click on create new table.


2. in the right pane give table name and column names as shown. (dont give space in 'full name' instead give 'full_name' or 'fullname')

3. scroll the winow to the right till you see A_I column as shown.

4. tick the first line (which we have used as id), 'add index' box will appear.
just click here go (at the bottom).
you will be redirected to table list as shown.

6. open (click) your table again.

7. click on structure.
now suppose you don't want duplicates in 'username' column, click this column and click on 'unique' as shown

if you don't want duplicate when both the columns' value together, click both the columns and then click 'unique' as shown

if you understand create table commands:

here is the sql for above: CREATE TABLE accounts ( id int(11) NOT NULL AUTO_INCREMENT, username varchar(25) NOT NULL, fullname varchar(55) NOT NULL, PRIMARY KEY ( id ), UNIQUE KEY username ( username ) ) ENGINE=MyISAM DEFAULT CHARSET=latin1

with above table structure records will be autoincremented and duplicate names will not be added. (remember to handle duplicate entries error in you inserting querie with
INSERT IGNORE INTO
with this your query will be:

$statement = $link->prepare('INSERT IGNORE INTO accounts (username, fullname)
      VALUES (:username, :fname)');

or you can also use
ON DUPLICATE KEY)

Answer 6

First set your primary key (eg. id) if not set as auto increment

Second use multiple insertion value

INSERT IGNORE INTO accounts (username,fullname) VALUES ("p","k"),("c","s");

IGNORE keyword is use to duplicate

IF you want to see with PDO