Joining table mysql -- without double iteration - php

Question

Let me start by saying this should be a relatively simple problem which is / was made unnecessary complicated by bad Database design (not by me) that said im also no expert in mysql.
Consider the following
Table Schedule
Note how the columns homeID and visitorID contains the names of the teams and not the actual teamID's
In a bid to fix this I created a new table with columns containing teamID AND teamName as can be seen by below image.
Table Teams
My Problem(s)
I must get the teamID from table Teams for BOTH home team AND away team
So I created the Teams table and this simple script:
SELECT schedule.*, teams.*
FROM schedule
JOIN teams ON schedule.homeID = teams.teamName OR schedule.visitorID = teams.teamName
WHERE schedule.gameID = 411
LIMIT 1 #added Limit1 else the code generates to rows
Output of mysql Script
Limit 1
Notice above how teamID is only generated for 1 team with Limit 1
No Limit Statement (Double Iteration)
Notice above how teamID can get retrieved for BOTH teams. Problem is its doing a double iteration.
TLDR; The above presents the following problems
Firstly the script will generate two outputs one for home team and once for away team. As to be expected however I cant have that.
As a workaround to Problem number 1 -- I added Limit 1 the problem I get with Limit though is that it only gives back a single teamID (as to be expected, I guess)
Question
How can I get BOTH teamID's from table teams with a single iteration? Hope this make sense....
Extra
A demo of application with hard coded team names looks like this (just to give an idea of what they are trying to achieve)

Answer 1

Sounds like you want to join teams twice to schedule.
SELECT s.*,
th.*,
ta.*
FROM schedule s
INNER JOIN teams th
ON s.homeid = th.teamname
INNER JOIN teams ta
ON s.visitorid = ta.teamname
WHERE s.gameid = 411;

Answer 2

I guess that you want to show both team in one row instead of two rows.
If yes, then you need to join the table teams twice.
Consider this demo: http://www.sqlfiddle.com/#!9/bb5e61/1
This join will collect both teams into one row:
SELECT s.*,
t1.teamId as homeId_teamId,
t1.teamCode as homeId_teamCode,
t1.teamName as homeId_teamName,
t2.teamId as visitorId_teamId,
t2.teamCode as visitorId_teamCode,
t2.teamName as visitorId_teamName
FROM Schedule s
JOIN Teams t1 ON s.homeId = t1.teamName
JOIN Teams t2 ON s.visitorId = t2.teamName;
| id | homeId | visitorId | homeId_teamId | homeId_teamCode | homeId_teamName | visitorId_teamId | visitorId_teamCode | visitorId_teamName |
|----|--------|-----------|---------------|-----------------|-----------------|------------------|--------------------|--------------------|
| 1 | Poland | Colombia | 1 | PL | Poland | 2 | CO | Colombia |
However you can also consider LEFT joins instead on INNER joins, which will work in a case where there is no relevant data in the TEAMS table:
SELECT s.*,
t1.teamId as homeId_teamId,
t1.teamCode as homeId_teamCode,
t1.teamName as homeId_teamName,
t2.teamId as visitorId_teamId,
t2.teamCode as visitorId_teamCode,
t2.teamName as visitorId_teamName
FROM Schedule s
LEFT JOIN Teams t1 ON s.homeId = t1.teamName
LEFT JOIN Teams t2 ON s.visitorId = t2.teamName;
| id | homeId | visitorId | homeId_teamId | homeId_teamCode | homeId_teamName | visitorId_teamId | visitorId_teamCode | visitorId_teamName |
|----|----------|-----------|---------------|-----------------|-----------------|------------------|--------------------|--------------------|
| 1 | Poland | Colombia | 1 | PL | Poland | 2 | CO | Colombia |
| 3 | Ya Majka | Poland | (null) | (null) | (null) | 1 | PL | Poland |
| 2 | Ya Majka | Rossija | (null) | (null) | (null) | (null) | (null) | (null) |
Here are the scripts that make up the tables from the examples
CREATE TABLE Schedule(
id int, homeId varchar(20),visitorId varchar(20)
);
INSERT INTO Schedule VALUES
(1, 'Poland', 'Colombia' ),(2,'Ya Majka','Rossija'),
(3,'Ya Majka','Poland');
CREATE TABLE Teams(
teamId int, teamCode varchar(10), teamName varchar(20)
);
INSERT INTO Teams VALUES
(1, 'PL', 'Poland' ),(2,'CO','Colombia'),(3,'US','United States');

Answer 3

You can use a subquery (two of them in the same query) to solve this:
select
gameID,
weekNum,
gameTimeEastern,
(select teamName from teams where teamID = schedule.homeID) as homeName,
homeScore,
(select teamName from teams where teamID = schedule.visitorID) as visitorName,
visitorScore from schedule;
This doesn't get all the columns from schedule, just an example to show how it works. If you need various queries (including select *, though this isn't a good practice except for testing), you could create a view based on a query like the above (with ALL columns from schedule, except homeID and visitorID that get replaced with sub-queries from the teams table). Then you can place queries against that view - and they will work like the original table where you had team names directly in it.