lancedb/docs/web/sql/dql/scalar-functions.mdx

---
title: "Scalar functions"
sidebarTitle: "Scalar Functions"
description: "The per-row function set: math, string, regex, date/time, array, struct, and what Lance adds."
icon: calculator
keywords: ["scalar functions", "string functions", "math functions", "regex", "array functions", "json"]
availability:
  embedded: unavailable
  enterprise: available
---

Functions that take a value and return a value, one row at a time. The set is
based on DataFusion's registration plus Lance and deployment-specific
functions. The names below are selected examples, not an exhaustive catalog
for every deployment. Availability depends on the deployed version and build.

For per-group functions see [Aggregation](/sql/dql/aggregation); for per-window,
[Window functions](/sql/dql/window).

## Math {#math}

```text
abs  ceil  floor  round  trunc  signum  power  sqrt  cbrt  exp
ln  log  log2  log10  factorial  gcd  lcm  pi  random  nanvl
isnan  iszero  cot  degrees  radians  to_degrees  to_radians
sin  cos  tan  asin  acos  atan  atan2
sinh  cosh  tanh  asinh  acosh  atanh
```

## String {#string}

```text
ascii  bit_length  btrim  chr  concat  concat_ws  contains  ends_with
starts_with  levenshtein  lower  upper  ltrim  rtrim  octet_length
repeat  replace  split_part  to_hex  uuid
```

Unicode-aware variants:

```text
character_length  find_in_set  initcap  left  right  lpad  rpad
reverse  strpos  substr  substr_index  substring  translate
```

<Note>
For keyword matching on a text column, [`contains_tokens`](/sql/dql/contains-tokens)
is index-accelerated where `contains` and `LIKE` are not.
</Note>

## Regular expressions {#regex}

```text
regexp_count  regexp_instr  regexp_like  regexp_match  regexp_replace
```

## Date and time {#datetime}

```text
current_date  current_time  date_bin  date_part  date_trunc
from_unixtime  to_unixtime  make_date  make_time  to_char
to_date  to_time  to_local_time
```

`date_bin` is the one worth knowing for analytics: it buckets timestamps into
fixed-width intervals, which is how you build a time series without a
self-join.

<CodeGroup>
```sql SQL icon="database"
SELECT date_bin(INTERVAL '1 hour', created_at) AS hour, count(*)
FROM events
GROUP BY hour
ORDER BY hour
```
</CodeGroup>

## Arrays and maps {#arrays}

```text
make_array  array_has  array_filter  array_transform  array_any_match
array_compact  array_normalize  array_slice  arrays_zip  cardinality
flatten  range  generate_series
```

```text
map  map_keys  map_values  map_entries  map_extract
```

Distance functions over arrays: `cosine_distance`, `distance`,
`exact_distance`, `inner_product`. Only `distance` and `exact_distance`
take an options string, and only `distance` can plan as vector search; see
[Vector distance functions](/sql/dql/vector-distance).

## Structs and fields {#structs}

```text
named_struct  get_field  coalesce  nullif  nvl  nvl2  greatest  least
union_extract  union_tag
```

## Crypto and encoding {#crypto}

```text
digest  md5  sha224  sha256  sha384  sha512  encode  decode
```

## Type functions {#type}

```text
arrow_cast  arrow_try_cast  arrow_typeof  arrow_field  arrow_metadata
with_metadata  version
```

Use `arrow_typeof` to inspect the Arrow data type of a column or expression:

<CodeGroup>
```sql SQL icon="database"
SELECT arrow_typeof(vector) FROM documents LIMIT 1
-- FixedSizeList(Field { name: "item", data_type: Float32, .. }, 1536)
```
</CodeGroup>

`arrow_cast` casts to an Arrow type by name, reaching types SQL has no spelling
for. See [Data types](/sql/data-types).

## What Lance adds {#lance}

These are registered by Lance on top of DataFusion's set, each with its own
reference page:

| | |
| --- | --- |
| [`contains_tokens`](/sql/dql/contains-tokens) | index-accelerated keyword predicate, usable in `WHERE` |
| [`ivf_partition`](/sql/dql/ivf-partition) | assign each row to its trained IVF index partition |
| [`blob_descriptor`](/sql/dql/blob-descriptor) | a BlobV2 column's payload location, without reading it |
| [JSON accessors](/sql/dql/json-functions) | `json_get` and its typed variants, `json_extract`, and more |

### Geospatial {#geo}

<Warning>
Lance defines `st_*` functions on GeoArrow, but they sit behind a build feature
**LanceDB does not ship**. Calling one returns an error naming the missing
feature rather than an unknown-function error, and the spatial index is gated
the same way.
</Warning>

## Additional scalar functions {#escape-hatch}

SQL queries can call functions registered with the server, including functions
not listed on this page. Consult
[DataFusion's scalar function reference](https://datafusion.apache.org/user-guide/sql/scalar_functions.html)
for version 54. Functions documented for a newer DataFusion release may not be
available in your LanceDB Enterprise version.