Display multiple sql queries and order them by timestamp - php

Question

I am creating a CRM for myself. My database contains four tables. In a section of my site I want to while loop all [note] and [task] that are connected to a [contact].
[link] (Linking contact to task)
'id' 'contact_id' 'task_id'
'1' '1' '1'
[contact]
'id' 'contact_name'
'1' 'Robert'
[task]
'id' 'description' 'due_date'
'1' 'Call to say hello' '2016:06:13'
[note] (Note link directly to the contact)
'id' 'contact_id' 'text' 'date_entered'
'1' '1' 'I met Robert on the weekend.' '2016:06:12'
The only way I know at the moment is creating two seperate queries. One to select and display the task information...
$contact_id_for_example = '1'
$find_the_link = $mysqli->query("SELECT * FROM link WHERE contact_id = '$contact_id_for_example'");
if($find_the_link->num_rows != 0){
while($link_rows = $find_the_link->fetch_assoc())
{
$link_task_id = $link_rows['task_id'];
$find_the_task = $mysqli->query("SELECT * FROM task WHERE id = '$link_task_id' ORDER BY due_date");
if($find_the_task->num_rows != 0){
while($task_rows = $find_the_task->fetch_assoc())
{
$task_description = $task_rows['description'];
echo '<li>'.$task_description.'</li>';
}
}
..and one to display the note information..
$note_select = $mysqli->query("SELECT * FROM note WHERE contact_id = '$contact_id_for_example' ORDER BY 'date_entered'");
if($note_select->num_rows != 0){
while($note_rows = $note_select->fetch_assoc())
{
$note_text = $note_rows['text'];
echo '<li>'.$note_text.'</li>';
}
}
The problem with my method is that the above code would print all of the matching tasks first then all of the notes below that. Even if the first note was entered/due well before the task they will always print after the tasks.
I have looked into JOINS and don't see how that would work in this instance due the [link] table interconnecting the [contact] and [task] table.
I have also searched around this site and others and noticed Multiple Queries. but from what I have read so far this doesn't solve the issue either.
Here is my attempt:
$test_contact_id = '1068';
$query = "SELECT * FROM link WHERE contact_id = '$test_contact_id';";
$storing_link = $query->num_rows;
$find_task_id = $storing_link->fetch_fields();
$find_task_id->task_id;
$query .= "SELECT * FROM task WHERE id = '$find_task_id';";
$storing_task = $query->num_rows;
$find_task_description = $storing_task->fetch_fields();
$task_description->text;
$query .= "SELECT * FROM note WHERE contact_id = '$test_contact_id';";
$storing_note = $query->num_rows;
$find_note_text = $storing_note->fetch_fields();
$note_text = $find_note_text->text;
if($mysqli->multi_query($query)){
echo '<p>'.$task_description.' :: '.$note_text.'</p>';
}

Answer 1

JOINs are EXACTLY what you want. You just need a bit of logic to detect when you're moving between record sets. e.g. a simple state machine:
SELECT ...
ORDER BY table1.foo, table2.bar, table3.baz
$prev1 = $prev2 = $prev3 = null;
while($row = fetch()) {
if ($row['table1.foo'] != $prev1) {
start a new table1 output
$prev1 = $row['table1.foo'];
}
... repeat for tables 2&3,
... output "core" data
}