---
title: How Query Builders Work
noindex: true
canonical: https://docs.paradedb.com/documentation/advanced/overview
---

In addition to basic [match](/v2/full-text/match), [phrase](/v2/full-text/phrase), and
[term](/v2/full-text/term) queries, additional advanced query types are exposed as query builder functions.

Query builder functions use the `@@@` operator. `@@@` takes a column on the left-hand side and a query builder function on the
right-hand side. It means "find all rows where the column matches the given query."

For example:

```sql
SELECT description, rating, category
FROM mock_items
WHERE description @@@ pdb.regex('key.*rd');
```

<Accordion title="Expected Output">
```csv
       description        | rating |  category
--------------------------+--------+-------------
 Ergonomic metal keyboard |      4 | Electronics
 Plastic Keyboard         |      4 | Electronics
(2 rows)
```
</Accordion>

This uses the [regex](/v2/query-builder/term/regex) query builder function to match all rows where `description` matches the regex expression `key.*rd`.

## When to Use Query Builder Functions

For most use cases, we recommend using the [full text search](/v2/full-text) operators instead of query builder
functions. However, there are three situations where query builder functions are useful.

1. If you need an advanced query type, like [regex](/v2/query-builder/term/regex).

2. If you want to leverage ParadeDB's support for [JSON query syntax](/v2/query-builder/json).

3. If you want to **force query pushdown** into the ParadeDB [custom scan](/welcome/architecture#custom-scan). There are some cases where queries that don't contain a ParadeDB
operator can be more efficiently executed by ParadeDB vs. standard Postgres, like [TopN]() or [aggregate]() queries. In this situation, adding an `AND ... pdb.all()` `WHERE` clause is semantically equivalent and forces ParadeDB to execute the query.

```sql
-- Top N executed by standard Postgres
SELECT * FROM mock_items
WHERE rating IS NOT NULL
ORDER BY rating
LIMIT 5;

-- Top N executed by ParadeDB
SELECT * FROM mock_items
WHERE rating IS NOT NULL AND id @@@ pdb.all()
ORDER BY rating
LIMIT 5;
```