How do I order by average rating?

I have a table of facilities and reviews for facilities which I can join via the facilityTable.id = review.facilityId columns. I want to select the top ten according to average reviews. How can I do that? Here's what I have so far:
const facilities = await db
.select({
id: facilityTable.id,
name: facilityTable.name,
averageRating: avg(reviewTable.rating).mapWith(Number),
totalReviews: count(reviewTable.id),
city: {
slug: cityTable.slug,
regionSlug: cityTable.regionSlug,
},
})
.from(facilityTable)
.innerJoin(cityTable, eq(facilityTable.cityId, cityTable.id))
.leftJoin(reviewTable, eq(facilityTable.id, reviewTable.facilityId))
.groupBy(facilityTable.id, cityTable.slug, cityTable.regionSlug)
.orderBy(
sortBy === SortBy.PRICE_LOW_TO_HIGH
? asc(facilityTable.minMonthlyRent)
: sortBy === SortBy.PRICE_HIGH_TO_LOW
? desc(facilityTable.maxMonthlyRent)
: sortBy === SortBy.RATING
? desc(avg(reviewTable.rating))
: // else SortBy.RECOMMENDED or undefined
desc(facilityTable.internalRating),
)
.limit(PAGE_SIZE)
.offset(PAGE_SIZE * (pageIndex - 1))
const facilities = await db
.select({
id: facilityTable.id,
name: facilityTable.name,
averageRating: avg(reviewTable.rating).mapWith(Number),
totalReviews: count(reviewTable.id),
city: {
slug: cityTable.slug,
regionSlug: cityTable.regionSlug,
},
})
.from(facilityTable)
.innerJoin(cityTable, eq(facilityTable.cityId, cityTable.id))
.leftJoin(reviewTable, eq(facilityTable.id, reviewTable.facilityId))
.groupBy(facilityTable.id, cityTable.slug, cityTable.regionSlug)
.orderBy(
sortBy === SortBy.PRICE_LOW_TO_HIGH
? asc(facilityTable.minMonthlyRent)
: sortBy === SortBy.PRICE_HIGH_TO_LOW
? desc(facilityTable.maxMonthlyRent)
: sortBy === SortBy.RATING
? desc(avg(reviewTable.rating))
: // else SortBy.RECOMMENDED or undefined
desc(facilityTable.internalRating),
)
.limit(PAGE_SIZE)
.offset(PAGE_SIZE * (pageIndex - 1))
7 Replies
zerokelvin
zerokelvinOP2mo ago
This gets a value without error, but doesn't seem to be returning everything. It's returning facilities that have no reviews, but not the facilities with the highest average reviews
DoggeSlapper
DoggeSlapper2mo ago
orderBy(sql`COALESCE(AVG(${reviewTable.rating}), 0) DESC`
orderBy(sql`COALESCE(AVG(${reviewTable.rating}), 0) DESC`
did u tr something like that?
zerokelvin
zerokelvinOP2mo ago
I think something like did work for me, yes, but I ended up just making a materialized view
DYELbrah
DYELbrah2mo ago
The ternary operators back to back is painful
zerokelvin
zerokelvinOP2mo ago
How would you do it instead?
Kuba
Kuba2mo ago
Another option is to use an additional field ex.: averageRating that you update on every new review. It doesn't adhere to the normalization rules, but does it job well and saves some computation from the database side I mean, you have to compute it for every new review, but it avoid you from having to run AVG aggregation on every retrieval of facilities, since it's just another "computed" attribute
DYELbrah
DYELbrah2mo ago
Probably a switch statement? or just a separate function that returns asc or desc Would also be nicely testable
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