How to escape SELECT COUNT (*) and create a table - php

Question

I am fairly new to working with PHP and WordPress. I tried exploring how to escape and sanitize, and I got a little confused along the way.
I'd like to echo out the contents of an entire table from the database. I am unsure whether there is a better way of both creating a table in a more structured way, and I can't figure out how to escape the data when I don't select specific data from the database. Maybe i'm just confused. Any help or pointers is highly appreciated.
I found the code somewhere on Stack Overflow, edited a little and tried to understand it. I understand it now, but I am still confused on where to go from here.
<?php
$results = $wpdb->get_results( "SELECT * FROM user"); // Query to fetch data from database table and storing in $results
if(!empty($results)) // Checking if $results have some values or not
{
echo "<table width='100%' border='0' id='userTable'>"; // Adding <table> and <tbody> tag outside foreach loop so that it wont create again and again
echo "<tbody>";
echo "<tr>"; // Adding rows of table inside foreach loop
echo "<th>E-mail</th>" . "<th>Fornavn</th>" . "<th>Efternavn</th>" . "<th>Registreret den</th>";
echo "</tr>";
foreach($results as $row){ //putting the user_ip field value in variable to use it later in update query
echo "<td colspan='3'><hr size='2'></td>";
echo "<tr>";
echo "<td>" . esc_attr($row->email) . "</td>" . "<td>" . $row->firstname . "</td>" . "<td>" . $row->lastname . "</td>" . "<td>" . $row->signuptime . "</td>"; //fetching data from user_ip field
}
echo "</tbody>";
echo "</table>";
}
?>

Answer 1

This part...
foreach($results as $row){
//putting the user_ip field value in variable to use it later in update query
echo "<td colspan='3'><hr size='2'></td>";
echo "<tr>";
echo "<td>" . esc_attr($row->email) . "</td>" . "<td>" . $row->firstname . "</td>"
. "<td>" . $row->lastname . "</td>" . "<td>" . $row->signuptime . "</td>";
//fetching data from user_ip field
}
...would product html like
{3 columns}{content}{3 columns end}{row start}
{column start}{content}{column end} * 4
{3 columns}{row start}
{column start}{content}{column end} * 4
{3 columns}{row start}
{column start}{content}{column end} * 4
etc
What you want in your loop is probably:
{row start}{4 columns}{content}{4 columns end}{row end}
{row start}{column start}{content}{column end} * 4{row end}
which would look like this:
foreach($results as $row){
//putting the user_ip field value in variable to use it later in update query
echo "<tr><td colspan='4'><hr size='2'></td></tr>";
echo "<tr><td>" . esc_attr($row->email) . "</td>" . "<td>" . $row->firstname . "
</td><td>" . $row->lastname . "</td>" . "<td>" . $row->signuptime . "</td></tr>";
//fetching data from user_ip field
}
In your SQL-statement on your first row: SELECT * FROM user , all fields are returned into the $results array of objects. If you want to specify which fields are returned you simply include them instead of the *, e.g. SELECT id, email, firstname, lastname FROM user