MYSQL select query on multiple tables

Question

I'm not seeing a clean way to write this query without subselects which I avoid because they are generally not portable, and harder to read and debug than individual queries.

Table A has exactly 2 foreign keys to table B, which are always different, but always defined. Sort of like:

MARRIAGE_TABLE
M_KEY
LAST_NAME
PERSON_HUSBAND_FK
PERSON_WIFE_FK

PERSON_TABLE
PERSON_KEY
SEX 
FIRST_NAME

The PERSON_HUSBAND_FK will always point at a SEX=MALE, and the WIFE_FK will always point at a female. There will always be one of each. (this is in no way a statement on same-sex marriage BTW I'm all for it)..

I want to create a result like:

MARRIAGE   HUSBAND     WIFE
--------   -------     ----
SMITH        TOM        KATHY
JONES        BILL       EVE

My current approach is to get all records from the MARRIAGE TABLE and store them in a hash. Then I augment the hash with names {wife_name} and {husband_name} using 2 more queries using the husband and wife FK's. Then I format and print the hash. It works, but I'm not wild about 3 queries per row.

I'm not sure I ever encountered a table having >1 FK to another table. I've done years of table-design, but I'm not really sure this design even meets normalization. It seems like no, to me. Like they created a many-many without an intermediate table; a cheat?

Answer 1

Just join table PERSON_TABLE twice:

SELECT m.last_name AS marriage, p1.first_name AS husband, p2.first_name AS wife 
FROM marriage_table m
INNER JOIN person_table p1 ON p1.person_key = m.person_husband_fk
INNER JOIN person_table p2 ON p2.person_key = m.person_wife_fk