need help building one mysql query comparing a variable with two tables - php

Question

I have built 2 queries that compares the $project_id variable to the 2 tables MEETING & MEETING_AGENDA shown in the flow diagram below:
+---------------------+
+------------+ | MEETING_AGENDA |
| MEETING | +---------------------+
+------------+ | meeting_agenda_id |
| meeting_id |----->| meeting_id |
$project_id --->| project_id | | meeting_agenda_name |
+------------+ +---------------------+
The logic behind this flow diagram is, I have stored a variable called $project_id which acts as the input. If the $project_id = MEETING.project_id then I need to store a list of the MEETING.meeting_id's. There are multiple duplicates of project_id's in MEETING resulting in an array of meeting_id's (just for clarification). If any of the MEETING.meeting_id's = MEETING_AGENDA.meeting_id then print meeting_agenda_name.
My messy attempt (which works) looks like this:
$project_id = $_SESSION['PROJECT_ID'];
$query1 =
"
SELECT meeting_id, meeting_project_id
FROM MEETING
WHERE project_id = $project_id
";
$result1 = mysqli_query($con, $query1) or die("Query error: " . mysqli_error($con));
while($row = mysqli_fetch_array($result1)){
$meeting_ids = $row['meeting_id'];
$query2 =
"
SELECT *
FROM MEEITNG_AGENDA
WHERE meeting_id = $meeting_ids
";
$result2 = mysqli_query($con, $query2) or die("Query error: " . mysqli_error($con));
while($row2 = mysqli_fetch_array($result2)){
echo $row2['meeting_agenda_name'] . "<br>"
}
}
I use 2 query's, I would like to clean this up into 1 query if possible. I have tried varies attempts at a single query but nothing has worked for me. Here is my latest attempt.
NEW QUERY:
$query =
"
SELECT MEETING.project_id, MEETING.meeting_id, MEETING_AGENDA.*
FROM MEETING
WHERE MEETING.project_id = $project_id
INNER JOIN MEETING.project_id
ON $project_id = MEETING.project_id
";
I apologize for my lack of mysql knowledge, but any help is appreciated.

Answer 1

You can get that information in a single query with the following:
SELECT m.project_id, m.meeting_id, ma.*
FROM MEETING m
INNER JOIN MEETING_AGENDA ma ON ma.meeting_id = m.meeting_id
WHERE m.project_id = $project_id