I have two Models related, Catalog and ProductCategory. The latter has a composed PK, \'id, language_id\'. Here are the models simplified:
var Catalog = sequelize
You can try this (Especially if you are using MariaDB) -
const Sequelize = require('sequelize'); const op = Sequelize.Op; Catalog.find({where: {id: itemId}, include: { model: models.ProductCategory, where: { language_id: {[op.col]: 'Catalog.language_id'} } } })