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Querying: Sorting
Basics
Starting from RavenDB 4.0, the server will determine possible sorting capabilities automatically from the indexed value, but sorting will not be applied until you request it by using the appropriate methods. The following queries will not return ordered results:
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.whereGreaterThan("UnitsInStock", 10)
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock'
where UnitsInStock > 10To start sorting, we need to request to order by some specified index field. In our case we will order by UnitsInStock in descending order:
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.whereGreaterThan("UnitsInStock", 10)
.orderByDescending("UnitsInStock")
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock'
where UnitsInStock > 10
order by UnitsInStock as long descForcing ordering type
OrderingType can be forced by passing OrderingType explicitly to one of the orderBy() methods.
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.whereGreaterThan("UnitsInStock", 10)
.orderByDescending("UnitsInStock", "String")
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock'
where UnitsInStock > 10
order by UnitsInStock descOrdering by Score
When a query is issued, each index entry is scored by Lucene (you can read more about Lucene scoring here) and this value is available in metadata information of a document under @index-score (the higher the value, the better the match). To order by this value you can use the orderByScore() or the orderByScoreDescending() methods:
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.whereGreaterThan("UnitsInStock", 10)
.orderByScore()
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock'
where UnitsInStock > 10
order by score()Chaining Orderings
It is also possible to chain multiple orderings of the query results.
You can sort the query results first by some specified index field (or by the @index-score), then sort all the equal entries by some different index field (or the @index-score).
This can be achieved by using the orderBy() (orderByDescending()) and orderByScore() (orderByScoreDescending()) methods.
const results = await session
.query({ indexName: "Products/ByUnitsInStockAndName" })
.whereGreaterThan("UnitsInStock", 10)
.orderBy("UnitsInStock")
.orderByScore()
.orderByDescending("Name")
.all();class Products_ByUnitsInStockAndName extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock,
Name = product.Name
})`;
}
}from index 'Products/ByUnitsInStockAndName'
where UnitsInStock > 10
order by UnitsInStock, score(), Name descRandom Ordering
If you want to randomize the order of your results each time the query is executed, use the randomOrdering() method (API reference here):
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.randomOrdering()
.whereGreaterThan("UnitsInStock", 10)
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock'
where UnitsInStock > 10
order by random()Ordering When a Field is Searchable
When sorting must be done on field that is Searchable, due to Lucene limitations sorting on such a field is not supported. To overcome this, create another field that is not searchable, and sort by it.
const results = await session
.query({ indexName: "Products/ByName/Search" })
.search("Name", "Louisiana")
.orderByDescending("NameForSorting")
.all();class Products_ByName_Search extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
Name = product.Name,
NameForSorting = product.Name
})`;
this.index("Name", "Search");
}
}from index 'Products/ByName/Search'
where search(Name, 'Louisiana')
order by NameForSorting descAlphaNumeric Ordering
Sometimes when ordering strings, it doesn't make sense to use the default lexicographic ordering.
For example, "Abc9" will come after "Abc10" because if treated as single characters, 9 is greater than 1.
If you want digit characters in a string to be treated as numbers and not as text, you should use alphanumeric ordering. In that case, when comparing "Abc10" to "Abc9", the digits 1 and 0 will be treated as the number 10 which will be considered greater than 9.
To order in this mode you can pass the "AlphaNumeric" type into orderBy() or orderByDescending():
const results = await session
.query({ indexName: "Products/ByUnitsInStock" })
.whereGreaterThan("UnitsInStock", 10)
.orderBy("Name", "AlphaNumeric")
.all();class Products_ByUnitsInStock extends AbstractIndexCreationTask {
constructor() {
super();
this.map = `docs.Products.Select(product => new {
UnitsInStock = product.UnitsInStock
})`;
}
}from index 'Products/ByUnitsInStock '
where UnitsInStock > 10
order by Name as alphanumeric
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