[Solved] How to check if a value exists in a database, then return the row of data

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Introduction

When working with databases, it is often necessary to check if a certain value exists in the database and then return the row of data associated with that value. This can be done using a variety of methods, depending on the type of database you are using. In this article, we will discuss how to check if a value exists in a database and then return the row of data associated with that value. We will also discuss the different methods that can be used to accomplish this task.

Solution

Assuming you are using a relational database such as MySQL, you can use the SELECT statement to check if a value exists in a database and return the row of data.

For example, if you wanted to check if a value exists in a table called ‘users’ with a column called ‘name’, you could use the following query:

SELECT * FROM users WHERE name = ‘value’;

This query will return the row of data if the value exists in the database, or an empty result set if the value does not exist.


Your code has a few issues:

  1. Don’t mix more than one library. You are using mysql_ and mysqli_ together.
  2. Don’t use mysql_* functions. They are deprecated.
  3. No need of mysqli_close() function.
  4. You don’t need to repeat the table.
  5. You are not printing anything from the query’s result.

The problem with your code is, you need to change this line:

$result = mysqli_query($link, "SELECT * FROM `fixtureDetails` WHERE `sportID`='$sp'");

To populate as a table, use the resultset and loop.

if (mysqli_num_rows($result)) {
  while (false != ($data = mysqli_fetch_assoc($result))) {
    // Do whatever with your data.
    var_dump($data);
  }
} else {
  echo "No records.";
}

Final Code

<?php
  $link = mysqli_connect("localhost", "root", "pizza","fixtures");

  if ($_POST['SPORT'] == "Football") {
    $sp = '1';
  }
  if ($_POST['SPORT'] == "Tennis") {
    $sp = '2';
  }
  if ($_POST['SPORT'] == "Swimming") {
    $sp = '3';
  }

  // Execute the query and save the resultset.
  $result = mysqli_query($link, "SELECT * FROM `fixtureDetails` WHERE `sportID`='$sp'");
  // Check if there are any rows returned.
  if (mysqli_num_rows($result)) {
    // If there are rows returned, save every row to $data.
    while (false != ($data = mysqli_fetch_assoc($result))) {
      // Do whatever with your data.
      var_dump($data);
    }
  } else {
    // If there are no records, display a message.
    echo "No records.";
  }
?>

If you want a function to send the response of the count, you can have something like this:

<?php
  function getCount() {
    $link = mysqli_connect("localhost", "root", "pizza","fixtures");

    if ($_POST['SPORT'] == "Football") {
      $sp = '1';
    }
    if ($_POST['SPORT'] == "Tennis") {
      $sp = '2';
    }
    if ($_POST['SPORT'] == "Swimming") {
      $sp = '3';
    }

    // Execute the query and save the resultset.
    $result = mysqli_query($link, "SELECT * FROM `fixtureDetails` WHERE `sportID`='$sp'");
    // Check if there are any rows returned.
    return mysqli_num_rows($result);
  }
?>

If you want just a true or false, you can do:

<?php
  function getCount() {
    $link = mysqli_connect("localhost", "root", "pizza","fixtures");

    if ($_POST['SPORT'] == "Football") {
      $sp = '1';
    }
    if ($_POST['SPORT'] == "Tennis") {
      $sp = '2';
    }
    if ($_POST['SPORT'] == "Swimming") {
      $sp = '3';
    }

    // Execute the query and save the resultset.
    $result = mysqli_query($link, "SELECT * FROM `fixtureDetails` WHERE `sportID`='$sp'");
    // Check if there are any rows returned.
    return (mysqli_num_rows($result) > 0);
  }
?>

6

solved How to check if a value exists in a database, then return the row of data


If you need to check if a value exists in a database and then return the row of data, there are a few different methods you can use. The most common approach is to use a SQL query to search the database for the value. This is the most efficient way to check if a value exists in a database, as it only requires one query to be executed. Another approach is to use a programming language such as PHP or Python to loop through the database and check each row for the value. This approach is less efficient, as it requires multiple queries to be executed.

To use a SQL query to check if a value exists in a database, you will need to use the SELECT statement. This statement will allow you to search the database for the value you are looking for. For example, if you wanted to check if a user with the username “John” exists in the database, you could use the following query:

SELECT * FROM users WHERE username = 'John'

This query will search the users table for a row with the username “John”. If a row is found, the query will return the row of data. If no row is found, the query will return an empty result set.

If you are using a programming language such as PHP or Python to check if a value exists in a database, you will need to loop through the database and check each row for the value. For example, if you wanted to check if a user with the username “John” exists in the database, you could use the following code:

for row in users:
if row['username'] == 'John':
return row
return None

This code will loop through the users table and check each row for the username “John”. If a row is found, the code will return the row of data. If no row is found, the code will return None.

In conclusion, there are a few different methods you can use to check if a value exists in a database and then return the row of data. The most efficient approach is to use a SQL query, while the less efficient approach is to use a programming language such as PHP or Python to loop through the database and check each row for the value.