Hasura - query for tags - null array supposed to return all results, but only returns items with tags - hasura

Question

I have a query:
query SearchProductData($tagId: [Int!]) {
product(where: { productTags: {_or: {tagId: {_in: $tagId}}}}) {
id
name
productTags {
tag {
id
name
}
}
}
}
and I pass in a variable of
{"tagId": null}
I would like to get back all product, regardless of if they have tags applied or not. What happens though is it retrieves only items with tags applied, not including the items with no tags.
the DB schema is
|- product
|
|-- productTags (one to many linking table of productIDs and tagIDs)
|
|--- tags
Any ideas how to write a query for this use case?

Answer 1

This is expected because of how the where clause is translating to a join (you can see the Generated SQL and Execution Plan query analysis by clicking Analyze in GraphiQL console.)
I don't think it's possible without injecting a bool expression. See below:
E.g.
query Test($expression: product_bool_exp) {
product(where: $expression) {
id
name
product_tags {
tag {
id
name
}
}
}
}
with argument
{
"expression": {"product_tags": {"tag_id": {"_in": [2]}}}
}
returns back:
{
"data": {
"product": [
{
"id": 1,
"name": "product_A",
"product_tags": [
{
"tag": {
"id": 1,
"name": "tag_1"
}
},
{
"tag": {
"id": 2,
"name": "tag_2"
}
}
]
}
]
}
}
And for the other case using the same query (where there are no tags passed in, and therefore all products we can use this variable value:
{
"expression": null
}
And we get back...
{
"data": {
"product": [
{
"id": 1,
"name": "product_A",
"product_tags": [
{
"tag": {
"id": 1,
"name": "tag_1"
}
},
{
"tag": {
"id": 2,
"name": "tag_2"
}
}
]
},
{
"id": 4,
"name": "product_D",
"product_tags": []
}
]
}
}
So you can dynamically construct that where expressions and pass that as an argument to the query.