PHP | mysqli_error() Function

PHP mysqli_error() Function


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

The built-in mysqli_error() function returns the description of the error which 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 function returns a string value that represents 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 PHP function was first introduced in PHP version 5 and it works in all the later versions.

Example1

The following example illustrates the usage of built-in 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 built-in 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

Following is another example of the built-in 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 going to be rounding up for this tutorial post. In our next tutorial, we are going to be discussing about the PHP mysqli_error_list() Function.

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