I'm not really looking for code, just a clue as to what to read up on as I have been beating my head against the wall with this one. I can do it in about three steps but I am trying to do it in one. 
Table1Field1 is in a one to many relationship to table2.field1
All fields are strings.

PHP:
The first table1 is like this:
id Field1 Field2 Field3
1 TagNo44 Y Yes
2 TagNo5 C No
3 TagNo127 Q Maybe
4 TagNo4 T Perhaps
5 TagNo88 Z Probably Not
6 TagNo17 P Could be
The second table2 is like this:
id Field1 Field2 Field3
1 TagNo44 Outfit6 30
2 TagNo44 Outfit14 70
3 TagNo127 Outfit14 100
4 TagNo4 Outfit3 100
5 TagNo88 Outfit3 50
6 TagNo88 Outfit8 50
7 TagNo5 Outfit7 100
8 TagNo17 Outfit92 100
Output table to be like this
id Field1 Field2
4 TagNo4 Outfit3&100
2 TagNo5 Outfit7&100
6 TagNo17 Outfit92&100
1 TagNo44 Outfit14&70&Outfit6&30
5 TagNo88 Outfit3&50&Outfit8&50
3 TagNo127 Outfit14&100
Table1Field1 is in a one to many relationship to table2.field1
All fields are strings.