PHP | mysqli_error() Function

PHP mysqli_error() Function


Hello folks! welcome back to another edition of our tutorial on PHP. In this tutorial guide, we are going to be discussing about the PHP mysqli_error() Function.

The built-in PHP mysqli_error() function returns the description of the error occurred during the last MYSQLi function call.

Syntax

Following below is the syntax to use this function -

mysqli_error($con)


Parameter Details

Sr.NoParameter & Description
1

con(Mandatory)

This is an object representing a connection to MySQL Server.


Return Value

This built-in PHP function returns a string value representing the description of the error from the last MYSQLi function call. If there are no errors this function returns an empty string.

PHP Version

This built-in PHP function was first introduced in PHP version 5 and works in all the later versions.

Example1

The following below is an example which demonstrates the usage of PHP mysqli_error() function (in a procedural style) -

<?php
   //Creating a connection
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   //Query to retrieve all the rows of employee table
   mysqli_query($con, "SELECT * FORM employee");

   //Error
   $error = mysqli_error($con);
   print("Error Occurred: ".$error);

   //Closing the connection
   mysqli_close($con);
?>

Output

When the above code is executed, it will produce the following result -

Error Occurred: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FORM employee' at line 1

Example2

In an object oriented style the syntax of this function is $con->error(). Following is the example of this function in an object oriented style $minus;

<?php
   //Creating a connection
   $con = new mysqli("localhost", "root", "password", "mydb");

   //Query to retrieve all the rows of employee table
   $con -> query("SELECT * FROM wrong_table_name");

   //Error 
   $error = $con ->error;
   print("Error Occurred: ".$error);

   //Closing the connection
   $con -> close();
?>

Output

When the above code is executed, it will produce the following result -

Error Occurred: Table 'mydb.wrong_table_name' doesn't exist

Example3

The following is another example of the PHP mysqli_error() function -

<?php
   //Creating a connection
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   //Query to SELECT all the rows of the employee table
   mysqli_query($con, "SELECT * FROM employee");
   print("Errors in the SELECT query: ".mysqli_error($con)."\n");

   //Query to UPDATE the rows of the employee table
   mysqli_query($con, "UPDATE employee set INCOME=INCOME+5000 where FIRST_NAME in (*)");
   print("Errors in the UPDATE query: ".mysqli_error($con)."\n");

   //Query to INSERT a row into the employee table
   mysqli_query($con, "INSERT INTO employee VALUES (Kennedy, 'Nkpara', 27, 'M', 13000, 106)");
   print("Errors in the INSERT query: ".mysqli_error($con)."\n");
  
   //Closing the connection
   mysqli_close($con);
?>

Output

When the above code is executed, it will produce the following result -

Errors in the SELECT query:
Errors in the UPDATE query: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '*)' at line 1
Errors in the INSERT query: Unknown column 'Archana' in 'field list'

Example4

Try the following example below -

<?php
   $connection_mysql = mysqli_connect("localhost","root","password","mydb");
   
   if (mysqli_connect_errno($connection_mysql)){
      echo "Failed to connect to MySQL: " . mysqli_connect_error();
   }
   
   if (!mysqli_query($connection_mysql,"INSERT INTO employee (FirstName) VALUES ('Jack')")){
      echo("Error description: " . mysqli_error($connection_mysql));
   }
   
   mysqli_close($connection_mysql);
?>

Output

When the above code is executed, it will produce the following result -

Error description: Unknown column 'FirstName' in 'field list'


Alright guys! This is where we are rounding up for this tutorial post. In our next tutorial, we will discuss about the PHP mysqli_error_list() Function.

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