Joined query missing records - mysql

Question

I have a database that contains a people table and another table with names for those people. For each person, there is at least one record in the names table, with one of those being set as the 'person_default_name_id' for that person, but other variations of that name in different languages. The idea is that the user who looks up the table will have a preferred language set (e.g. English, Spanish, Russian) and a preferred script set, which is based on their preferred language (e.g. if their preferred language is English or Spanish, the script would be "Latin", while if the preferred language is Russian, the script would be "Cyrillic"). It's a little complex and I'm wanting to display a list of names, but only display one name per person, and that one chosen name should be shown according to the best-fit for the user's chosen language and script.
The code below is what I'm trying:
SELECT
people.person_id,
names.name
FROM
`people`
LEFT JOIN
`names` ON names.person_id=people.person_id
LEFT JOIN
`languages` ON names.language_id = languages.language_id
LEFT JOIN
`language_scripts` ON languages.language_id = language_scripts.language_id
WHERE
(
/* 1st preference - display the default name for the person IF the default name's language writing system matches the user's writing system */
(people.person_default_name_id=names.name_id AND language_scripts.script_id = :user_script_id)
OR
/* 2nd preference - display the alternative name in the user's chosen language if an alternative name exists in that language */
names.language_id = :user_language_id
OR
/* 3rd preference - display the alternative name in the user's chosen writing system if an alternative name exists in that writing system */
language_scripts.script_id = :user_script_id
)
GROUP BY
people.person_id
ORDER BY
names.name ASC
Example data is below:
Table: people
person_id | person_default_name_id
------------------------------------
1 | 2
Table: names
name_id | name | person_id | language_id
--------------------------------------------
1 | George | 1 | 1
2 | Jorge | 1 | 2
3 | Джордж | 1 | 3
Table: languages
language_id | language
------------------------
1 | English
2 | Spanish
3 | Russian
Table: language_scripts
language_script_id | language_id | script_id
----------------------------------------------
1 | 1 | 1
2 | 2 | 1
3 | 3 | 2
Table: scripts
script_id | script
----------------------
1 | Latin
2 | Cyrillic
I'm finding that some of the expected records are not coming through. I'm guessing that there are improvements I could make to my query, but my skills are not quite advanced enough to know the best path. Can anyone see what I'm doing wrong?

Answer 1

I would suggest you put your where clause conditions in your select statement and return a "score" for each record. Remove it entirely from your where clause and it may give you insight into why you have missing records if they are returned with a 0 score.
Case when condition Then 5
when condition then 4
Etc...
else 0
End case
Once you have your results scored, you can order by your score descending and take the first one per person. Or add additional outer queries to only return the rows having the max score per person.
Apologies for answering from my phone.