Azkaban

I want to match a field to 10 tables. It appears in some tables once, in other tables twice, in other tables not at all. I can't seem to find the right join for the job. I either get too many rows, not enough rows or incorrect rows.
Can someone help please?

Table 1
=============
t1id | userid | flag | score
--------------------------
1 | 1003 | red | 10

2 | 1003 | red | 5

3 | 1005 | blue | 15

Table 2
=============
t2id | userid | flag | score
--------------------------
1 | 1012 | yellow | 7

2 | 1002 | green | 4

3 | 1001 | red | 1

Table 3
=============
t1id | userid | flag | score
--------------------------
1 | 1012 | orange | 10

2 | 1022 | blue | 10

3 | 1023 | blue | 10
================================================== ========
I want to join these three tables on the value of red and get no data for table 3 and two rows for table 1. So something like this should be the result:
----------------------
Result
=============
userid | flag | score
--------------------------
1003 | red | 10
1003 | red | 5
1001 | red | 1
================================================== ========