how create left join query with sails.js - sails.js

Question

I would like do a left join query in sails.js. I think i should use populate
I have three models
caracteristique{
id,
name,
races:{
collection: 'race',
via: 'idcaracteristique',
through: 'racecaracteristique'
},
}
race{
id,
name,
caracteristiques:{
collection: 'caracteristique',
via: 'idrace',
through: 'racecaracteristique'
}
}
RaceCarecteristique{
idrace: {
model:'race'
},
idcaracteristique: {
model: 'caracteristique'
},
bonusracial:{
type: 'number',
}
My data are:
Table Caracteristiques
id name
1 | strength
2 | dex
3 | Charisme
Table Race
id name
1 | human
2 | Org
TableRaceCarecteristique
idrace idcaracteristique bonusracial
1 | 2 | +2
This sql request give me for human, all caracteristiques and if exist bonusracial
'SELECT caracteristique.id, caracteristique.name, bonusracial
FROM caracteristique
LEFT OUTER JOIN (select idcaracteristique, bonusracial
from racecaracteristique
where idrace=$1 ) as q
ON q.idcaracteristique = caracteristique.id';
I have this result:
caracteristique.id, caracteristique.name, bonusracial
1 | strength | null
2 | dex | 2
3 | Charisme | null
How use populate to do this ?

Answer 1

When using a SQL-database adapter (MySQL, PQSL etc) you can utilise a method for performing actual, handwritten SQL statements. When all else fails, this might be your best bet to find an acceptable solution, within the framework.
The .sendNativeQuery() method sends your parameterized SQL statement to the native driver, and responds with a raw, non-ORM-mangled result. Actual database-schema specific tables and columns appear in the result, so you need to be careful with changes to models etc. as they might change the schema in the backend database.
The method takes two parameters, the parameterized query, and the array of values to be inserted. The array is optional and can be omitted if you have no parameters to replace in the SQL statement.
Using your already parameterized query from above, I'm sending the query to fetch the data for an "org" (orc perhaps?) in the example below. See the docs linked at the bottom.
Code time:
let query = `
SELECT caracteristique.id, caracteristique.name, bonusracial
FROM caracteristique
LEFT OUTER JOIN (select idcaracteristique, bonusracial
from racecaracteristique
where idrace=$1 ) as q
ON q.idcaracteristique = caracteristique.id`;
var rawResult = await sails.sendNativeQuery(query, [ 2 ]);
console.log(rawResult);
Docs: .sendNativeQuery()