---
title: Boosting
---

Boosting increases or decreases the impact of a specific query by multiplying its contribution to the overall BM25 score.

## Constant Boosting

To boost a query, cast the query to the `boost` type. In this example, the `shoes` query is weighted twice as heavily as the `footwear` query.

```sql
SELECT id, paradedb.score(id), description, category
FROM mock_items
WHERE description ||| 'shoes'::boost(2) OR category ||| 'footwear'
ORDER BY score DESC
LIMIT 5;
```

`boost` takes a numeric value, which is the multiplicative boost factor. It can be any floating point number between `-2048` and `2048`.

[Query builder functions](/v2/query-builder/overview) can also be boosted:

```sql
SELECT id, description, category, paradedb.score(id)
FROM mock_items
WHERE description @@@ pdb.regex('key.*')::boost(2)
ORDER BY score DESC
LIMIT 5;
```

Boost can be used in conjunction with other type casts, like [fuzzy](/v2/full-text/fuzzy):

```sql
SELECT id, description, category, paradedb.score(id)
FROM mock_items
WHERE description ||| 'shose'::fuzzy(2)::boost(2)
ORDER BY score DESC
LIMIT 5;
```

## Boosting by Field

The following query boosts the score of each row by multiplying it by the row's `rating`. This means that items with
the same score but a higher `rating` will score higher overall.

```sql
SELECT id, description, rating, paradedb.score(id) * rating as score
FROM mock_items
WHERE description ||| 'shoes'
ORDER BY score DESC
LIMIT 5;
```

<Note>
  Ordering by `paradedb.score(id) * rating` is less performant than ordering by
  just `paradedb.score(id)` over large tables.
</Note>