PHP / MySQL - Match against 2 tables

Question

I'm working with some MySQL tables that have a not so friendly structure.

Currently I have a query like the following:

$query = 'SELECT textID, subject FROM articles 
 WHERE (UPPER(subject) LIKE "%'.$string.'%") AND status = "1" 
 ORDER BY CASE WHEN subject LIKE "'.$search.' %" THEN 0 
 WHEN creator LIKE "'.$search.'%" THEN 1 
 WHEN email LIKE "'.$search.'%" THEN 2 ELSE 3 END, 
 subject LIMIT 10';

I then obviously run and get the results like so:

    $res = $db->query($query);
    $result = array();

    while($results = $res->fetch_assoc()) {
    $result[] = $results;
    }

Now that I've pulled the data from the database, I now need to match it against data from a second table so that I can get/use only the results that match.

I want to now run the above array, specifically the "textID" retrieved for each result, against a second table to only use the results from the array that match the "textID" in a second table.

For example: Let's say the above query returned the following (NOTE: these results will be dynamic based on the "string" used in the query):

    Table: articles

    textID ----- Subject
    1       |     Test 
    4       |     Test 2
    25      |     Test 3
    33      |     Test 4
    51      |     Test 5

I want to run a second query (or implement it into the original query) that matches the "textID" up against any entries in a second table that share the same textID.

So if the second MySQL table has the following matching textID's:

    Table: altarticles

    textID 
    1
    25
    51

I'd want to scrap the original "$result[]" and create a new array that only contains the matching results:

    textID ----- Subject
    1       |     Test 
    25      |     Test 3
    51      |     Test 5

How would one go about doing this?

Answer 1

This should be accomplished easily by using a JOIN clause. JOIN altarticles on the TextID field. Alias each table articles a and altarticles aa and SELECT the aa.subject instead of the original table's subject.

A regular JOIN is also called an inner join meaning that only the rows match for the conditions for both tables are displayed.

$query = '
    SELECT
        a.textID, 
        a.subject 
    FROM articles a
    JOIN altarticles aa ON (a.textID = aa.textID)
    WHERE 
        (UPPER(a.subject) LIKE "%'.$string.'%") 
        AND a.status = "1" 
        ORDER BY CASE 
            WHEN a.subject LIKE "'.$search.' %" THEN 0 
            WHEN a.creator LIKE "'.$search.'%" THEN 1 
            WHEN a.email LIKE "'.$search.'%" THEN 2 
            ELSE 3 END, a.subject 
        LIMIT 10
';