How do I count specific, smaller groups of information in one large table?

Question

Hello all,
I have a feeling the answer to this is right under my nose, but somehow, it is evading me.
I would like to be able to count how many photos are in any specific gallery. Why? Well, on my TOC page, I thought it would be cool to show  the user how many photos were in any given gallery displayed on the screen as part of all the gallery data I'm presenting. It's not necessary, but I believe it adds a nice touch. My  thought was to have one massive table containing all the photo information and another massive table containing the gallery  information, and currently I do. I can pull various gallery information  based on user selections, but accurately counting the correct number of  images per gallery is evading me.
In my DB, I have the table, 'galleries', which has several columns, but the two most relevant are g_id and g_spe. g_id is the primary key and is an AI column that represents also the gallery 'serial' number. g_spec is a value that will have one of 11 different values in it (not relevant for this topic.)
Additionally, there is the table, 'photos', and in this table are three columns:  p_id, g_id and p_fname. p_id is the primary key, g_id is the foreign key (primary key of the 'galleries' table) and p_fname contains the filename of each photo in my ever-expanding gallery.
Here's the abbreviated contents of the galleries table showing only the first 2 columns:
(`g_id`, `g_spec`, etc...)
(1, 11, etc...),
(2, 11, etc...),
(3, 11, etc...),
(4, 11, etc...),
(5, 12, etc...),
(6, 13, etc...)
Here's the contents of my photos table so far, populated with test images:
(`p_id`, `g_id`, `p_fname`)
(1, 1, '1_DSC1155.jpg'),
(2, 1, '1_DSC1199.jpg'),
(3, 1, '1_DSC1243.jpg'),
(4, 1, '1_DSC1332.jpg'),
(5, 1, '1_DSC1381.jpg'),
(6, 1, '1_DSC1421.jpg'),
(7, 1, '1_DSC2097.jpg'),
(8, 1, '1_DSC2158a.jpg'),
(9, 1, '1_DSC2204a.jpg'),
(10, 1, '1_DSC2416.jpg'),
(11, 1, '1_DSC2639.jpg'),
(12, 1, '1_DSC3768.jpg'),
(13, 1, '1_DSC3809.jpg'),
(14, 1, '1_DSC4226.jpg'),
(15, 1, '1_DSC4257.jpg'),
(16, 1, '1_DSC4525.jpg'),
(17, 1, '1_DSC4549.jpg'),
(18, 2, '2_DSC1155.jpg'),
(19, 2, '2_DSC1199.jpg'),
(20, 2, '2_DSC1243.jpg'),
(21, 2, '2_DSC1332.jpg'),
(22, 2, '2_DSC1381.jpg'),
(23, 2, '2_DSC1421.jpg'),
(24, 2, '2_DSC2097.jpg'),
(25, 2, '2_DSC2158a.jpg'),
(26, 2, '2_DSC2204a.jpg'),
(27, 2, '2_DSC2416.jpg'),
(28, 2, '2_DSC2639.jpg'),
(29, 2, '2_DSC3768.jpg'),
(30, 2, '2_DSC3809.jpg'),
(31, 2, '2_DSC4226.jpg'),
(32, 2, '2_DSC4257.jpg'),
(33, 2, '2_DSC4525.jpg'),
(34, 2, '2_DSC4549.jpg'),
(35, 3, '3_DSC1155.jpg'),
(36, 3, '3_DSC1199.jpg'),
(37, 3, '3_DSC1243.jpg'),
(38, 3, '3_DSC1332.jpg'),
(39, 3, '3_DSC1381.jpg'),
(40, 3, '3_DSC1421.jpg'),
(41, 3, '3_DSC2097.jpg'),
(42, 3, '3_DSC2158a.jpg'),
(43, 3, '3_DSC2204a.jpg'),
(44, 3, '3_DSC2416.jpg'),
(45, 3, '3_DSC2639.jpg'),
(46, 3, '3_DSC3768.jpg'),
(47, 3, '3_DSC3809.jpg'),
(48, 3, '3_DSC4226.jpg'),
(49, 3, '3_DSC4257.jpg'),
(50, 3, '3_DSC4525.jpg'),
(51, 3, '3_DSC4549.jpg');
For now, each gallery has 17 images which was just some random number I chose.
I need to be able to write a query that says, tell me how many photos are in a specific photoset (in the photos table) based on the number in galleries.g_id  and photos.g_id being equal.
As you see in the photos table, the p_id column is an AI column (call it photo serial numbers), and the g_id column assigns each specific photo to a specific gallery number that is equal to some gallery ID in the galleries.g_id table. SPECIFICALLY, for example I would want to have the query count the number of rows in the photos table whose g_id = 2 when referenced to g_id = 2 in the galleries table.
I have been messing with different DISTINCT and COUNT methods, but all seem to be limited to working with just one table, and here, I need to reference two tables to acheive my result.
Would this be better if each gallery had its own table?
It should be so bloody simple, but it's just not clear.
Please let me know if I have left out any key information, and thank you all in advance for your kind and generous help.
Sincerely,
wordman

Answer 1

bregent,
I got it!
Here's the deal: the query that picks the subset of records:
$conn = dbConnect('query');
$sql = "SELECT *
        FROM galleries
        WHERE g_spec = '$spec%'
        ORDER BY g_id DESC
        LIMIT $startRow,".SHOWMAX;
$result = $conn->query($sql) or die(mysqli_error());
$galSpec = $result->fetch_assoc();
picks 3 at a time, and with each record is an individual gallery number (g_id). So, I went down into my code where a do...while loop runs through the data, displaying the info for each subset of records and I added another query:
$conn = dbConnect('query');
$getTotal = "SELECT COUNT(*)
            FROM photos
            WHERE g_id = {$galSpec['g_id']}
            GROUP BY g_id";
$total = $conn->query($getTotal);
$row = $total->fetch_row();
$totalPix = $row[0];
which uses the value in $galSpec['g_id']. I didn't know the proper syntax for including it, but when I tried the curly braces, it worked. I altered the number of photos in each gallery in the photos table so that each total is different, and the results display perfectly.
And as you can see, I used some of the code you suggested in the second query and all is well.
Again, thank you so much for being patient and lending me your advice and assistance!
Sincerely,
wordman