# Malloy

- Page: https://shared.btbytes.com/p/malloy
- Date: 2025-09-06

[Malloy](https://www.malloydata.dev) a modern language for analyzing,  
transforming, and modeling data.

```
run: duckdb.table('../data/airports.parquet') -> {
  select:
    id
    code
    city
  limit: 10
}
```

is equivalent to `SELECT id, code, city FROM airports LIMIT 10` in SQL.

In Malloy, all output fields have names.

One of the main benefits of Malloy is the ability to save common calculations into a data model. The data model is made of _sources_, which can be thought of as tables or views, but with additional information, such as joins, dimensions and measures.
```
source: airports is duckdb.table('../data/airports.parquet') extend {
  dimension: county_and_state is concat(county, ', ', state)
  measure: airport_count is count()
  measure: average_elevation is avg(elevation)
}
```

source can be imported into another using an import statement -- `import "airports.malloy"`

Sources can also contain named views.

Joins are also declared as part of sources:

```
source: flights is duckdb.table('../data/flights.parquet') extend {
  join_one: aircraft on tail_num = aircraft.tail_num
}
```

`where` is used for filtering. Filtering can be applied to  aggregate calculation (a mesure)

nested views produce with subtables.

Literals of type `date` and `timestamp` are notated with an `@`, e.g. `@2003-03-29` or `@1994-07-14 10:23:59`. Similarly, years (`@2021`), quarters (`@2020-Q1`), months (`@2019-03`), weeks (`@WK2021-08-01`), and minutes (`@2017-01-01 10:53`) can be expressed.

There is a special time literal `now`, referring to the current timestamp, which allows for relative time filters.

Numeric values can be extracted from time values, e.g. `day_of_year(some_date)` or `minute(some_time)`

Time ranges -- `@2003 to @2005`

The output from one stage of a query can be passed into another stage using `->` ( Pipeline )

## More Reading

- [SQL, Malloy, and the Art of the Renaissance](https://carlineng.com/?postid=sql-renaissance#blog)
- [Data is Rectangular and other Limiting Misconceptions](https://lloydtabb.substack.com/p/data-is-rectangular-and-other-limiting) from the creator of Malloy; Jan 2023.