Appending matching column onto each result row - php

Question

I'm not a SQL veteran so please excuse me if this is obvious; I'm learning.
I have two tables in a database for a wedding invite system; guests and invites. One invite (invitation) can contain many guests.
For purposes of creating a mail merge for the invites, I'm trying to select the firstname and lastname from the guest table, where the guest's inviteID is the same as the others; effectively returning on row of data containing the inviteID's data and a column each for the names of the guests.
My problem is I can return the data, but across multiple rows which won't work for the mail-merge. I can create a PHP script to do a work-around, but I would like to learn how this could be achieved in pure SQL.
Can anybody shed some light? Can this be done? Is this sheer madness?
Hoping to achieve:
*************************** 1. row ***************************
inviteID: 39
inviteURLSlug: thewinnetts
....
guestFirstName1: Sid
guestSurname1: Winnett
guestFirstName2: Claire
guestSurname2: Winnett
'invite' table:
+---------------------+--------------+
| Field | Type |
+---------------------+--------------+
| inviteID | int(11) |
| inviteURLSlug | varchar(64) |
| inviteQRValue | varchar(255) |
| inviteQRImageURL | varchar(255) |
| inviteAddress1 | varchar(32) |
| inviteAddress2 | varchar(32) |
| inviteAddress3 | varchar(32) |
| inviteCity | varchar(32) |
| inviteCounty | varchar(32) |
| inviteCountry | varchar(32) |
| invitePostcode | varchar(16) |
| inviteDateSend | datetime |
| inviteDateResponded | datetime |
| inviteCreated | datetime |
| inviteUpdated | timestamp |
+---------------------+--------------+
'guest' table:
+-------------------+--------------+
| Field | Type |
+-------------------+--------------+
| guestID | int(11) |
| inviteID | int(11) |
| guestFirstName | varchar(32) |
| guestSurname | varchar(32) |
| guestSide | varchar(8) |
| guestAttending | tinyint(1) |
| guestEmail | varchar(255) |
| guestPhone | varchar(32) |
| guestMobile | varchar(16) |
| guestAddress1 | varchar(32) |
| guestAddress2 | varchar(32) |
| guestAddress3 | varchar(32) |
| guestCity | varchar(32) |
| guestCounty | varchar(32) |
| guestCountry | varchar(32) |
| guestPostCode | varchar(16) |
| guestProfilePhoto | varchar(64) |
| guestFoodVeg | tinyint(1) |
| guestFoodReq | varchar(255) |
| guestTwitter | varchar(15) |
| guestFacebook | varchar(32) |
| guestPlusone | int(1) |
| guestCreated | datetime |
| guestUpdated | timestamp |
+-------------------+--------------+
Failed Join attempt and cropped results sample:
SELECT * FROM guest INNER JOIN invite on guest.inviteID = invite.inviteID \G
*************************** 64. row ***************************
guestID: 72
inviteID: 39
guestFirstName: Claire
guestSurname: Winnett
.......
*************************** 65. row ***************************
guestID: 73
inviteID: 39
guestFirstName: Sid
guestSurname: Winnett
.......

Answer 1

To achieve those results will require additional processing in PHP.
To do so, modify your query to this:
SELECT i.*,
g.guestFirstName,
g.guestSurname
GROUP_CONCAT(DISTINCT g.guestFirstName, '|', g.guestSurname ORDER BY g.guestSurname DESC) AS names
FROM invite i
INNER JOIN guest g ON i.inviteID = g.inviteID;
making sure to return your results as an array. From there, convert the concatenated results into an array then iterate through them to set the custom key name and corresponding value (assumes your query results are in array format with the variable name $queryresults):
$names = explode(',' $queryresults['names']);
unset($queryresults['names']);
$i = 1;
foreach ($names as $name) {
$split_name = str_split("|", $name);
$queryresults['guestFirstName' . $i] = $split_name[0];
$queryresults['guestSurname' . $i] = $split_name[1];
$i++;
}
This should give you your desired results.

Answer 2

SQL is not good at this sort of thing. It wants to work in sets, where all the items in the set are the same. You are asking for two items within the set to be smooshed together. Here is a possible solution:
SELECT
t1.inviteID,
t1.guestID,
t1.guestFirstName,
t1.guestSurname,
t2.guestFirstName AS guestFirstName2,
t2.guestSurname AS guestSurname2
FROM
guests as t1
LEFT OUTER JOIN
guests as t2
ON t1.inviteID = t2.inviteID
AND t1.guestID <> t2.guestID
WHERE
t1.guestID = (select min(t3.guestID) from guests as t3 where t3.inviteID = t1.inviteID)
;
The guests table is used twice, once to provide the first guest on each invite, and a second time, using a LEFT OUTER JOIN to provide the second. The LEFT OUTER ensures you still get the first even if there isn't a second. The other criteria are there to ensure you don't join a row to itself, and you only output the firsts, with the seconds attached (and not the other way around).
Here is a sample fiddle (in MySQL)

Answer 3

Is something like this what you are looking for?
Updated after your comment.
SELECT GROUP_CONCAT( DISTINCT `guest`.`guestFirstName`,`guest`.`guestSurname`, `invite`.`inviteURLSlug` ) FROM `guest`
LEFT JOIN `invite` ON `invite`.`inviteID` = `guest`.`inviteID`
WHERE `invite`.`inviteID` = 5
I just made two simple tables with minimal information for testing, but is easily expandable to whatever you have/want.
You are going to have some fields repeated since the number of rows is going to be related to the number of guests.