Include with where condition , but keep all result before including - express

Question

I am having a problem in querying inside the include
What I do is
const courses = await Course.findAll({
subQuery: false,
order: [ [ 'courseID', 'ASC' ] ],
include: [
{
model: CourseAvailable,
as: 'courseAvailable',
where: {
id: 350 // dummy condition only for asking here ( I had my purpose )
}
}
]
});
and the output
{
"success": true,
"data": [
{
"id": 20,
"courseID": "MTH102",
"courseName": "MATHEMATICS II",
"required": "{MTH101}",
"createdAt": "2020-05-19T17:30:44.085Z",
"updatedAt": "2020-05-19T17:30:44.085Z",
"courseAvailable": [
{
"id": 350,
"courseID": "MTH102",
"semester": 2,
"credit": 3,
"totalSeat": 150,
"section": "7",
"allowedGroup": "EET 1 A(0)",
"day": "จ.",
"start": "10.30",
"end": "12.30",
"classroom": "CB1103",
"createdAt": "2020-05-20T15:22:50.176Z",
"updatedAt": "2020-05-20T15:22:50.176Z"
}
]
}
]
}
From the output, I know that querying inside the include will only return the courses that found with the query inside the include ( as you can see there is only 1 Course in the returned data )
But I still want to query inside the include to make the include show only if it meets my condition ( like filtering the include )
But the thing is I still want to keep my other courses also which doesn't meet any condition
Expected Output
{
"success": true,
"data": [
{
"id": 19,
"courseID": "MTH101",
"courseName": "MATHEMATICS I",
"required": null,
"createdAt": "2020-05-19T17:30:44.085Z",
"updatedAt": "2020-05-19T17:30:44.085Z",
"courseAvailable": [] // showing empty array if none has met my query => still keep the data above
},
{
"id": 20,
"courseID": "MTH102",
"courseName": "MATHEMATICS II",
"required": "{MTH101}",
"createdAt": "2020-05-19T17:30:44.085Z",
"updatedAt": "2020-05-19T17:30:44.085Z",
"courseAvailable": [
{
"id": 350,
"courseID": "MTH102",
"semester": 2,
"credit": 3,
"totalSeat": 150,
"section": "7",
"allowedGroup": "EET 1 A(0)",
"day": "จ.",
"start": "10.30",
"end": "12.30",
"classroom": "CB1103",
"createdAt": "2020-05-20T15:22:50.176Z",
"updatedAt": "2020-05-20T15:22:50.176Z"
}
]
}
]
}

Answer 1

When using where inside an include, Sequilize will perform an inner join, as mentioned here. You would need to set the attribute required: false inside your include to perform a left join. Change your query to
const courses = await Course.findAll({
subQuery: false,
order: [ [ 'courseID', 'ASC' ] ],
include: [
{
model: CourseAvailable,
as: 'courseAvailable',
where: {
id: 350 // dummy condition only for asking here ( I had my purpose )
},
required: false
}
]
});