> ## Documentation Index
> Fetch the complete documentation index at: https://docs.e6data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SQL functions

> Every SQL function Query Engine supports, grouped by category, with syntax, arguments, return values and examples.

Query Engine supports 363 SQL functions. Each has its own page with syntax, arguments, return type, NULL behaviour and examples. Search for a function by name, or browse by category below.

Coming from another engine? [Equivalent functions and operators](https://docs.e6data.com/query/sql/function-mapping.md) maps common functions to their e6data names.

## Everyday SQL

> **[Aggregate functions](https://docs.e6data.com/query/sql/functions/aggregate)**
>
> 48 functions. Compute one result from a set of rows, such as a sum, count, average or approximate distinct count. Most can also run as window functions.

> **[Window functions](https://docs.e6data.com/query/sql/functions/window)**
>
> 7 functions. Rank rows and read values from neighbouring rows within a window. Aggregate functions can also run over windows.

> **[Conditional and conversion functions](https://docs.e6data.com/query/sql/functions/conditional)**
>
> 23 functions. Branch on conditions, handle NULLs, cast between types and read session context.

> **[String functions](https://docs.e6data.com/query/sql/functions/string)**
>
> 63 functions. Search, slice, combine, pad, format and transform text.

> **[Date and time functions](https://docs.e6data.com/query/sql/functions/date-time)**
>
> 78 functions. Build, convert, format, extract from and do arithmetic on dates, times and timestamps.

> **[Math functions](https://docs.e6data.com/query/sql/functions/math)**
>
> 53 functions. Arithmetic, rounding, logarithmic, trigonometric and other numeric functions.

## Semi-structured data

> **[JSON functions](https://docs.e6data.com/query/sql/functions/json)**
>
> 12 functions. Parse JSON, extract values from it and build JSON output.

> **[Array functions](https://docs.e6data.com/query/sql/functions/array)**
>
> 34 functions. Build, inspect, transform and flatten arrays.

> **[Map functions](https://docs.e6data.com/query/sql/functions/map)**
>
> 7 functions. Build maps and read their keys, values and entries.

> **[Struct functions](https://docs.e6data.com/query/sql/functions/struct)**
>
> 2 functions. Build structs (records with named fields).

> **[Table functions](https://docs.e6data.com/query/sql/functions/table)**
>
> 9 functions. Functions that return rows instead of a single value, such as exploding arrays or generating ranges.

## Pattern matching, hashing and bits

> **[Regular expression functions](https://docs.e6data.com/query/sql/functions/regex)**
>
> 8 functions. Match, extract and replace text with regular expressions.

> **[Hash functions](https://docs.e6data.com/query/sql/functions/hash)**
>
> 5 functions. Compute checksums and cryptographic digests.

> **[Bitwise functions](https://docs.e6data.com/query/sql/functions/bitwise)**
>
> 13 functions. Operate on the individual bits of integers.

> **[Bitmap functions](https://docs.e6data.com/query/sql/functions/bitmap)**
>
> 1 functions. Work with bitmaps.

## Specialised

> **[Geospatial functions](https://docs.e6data.com/query/sql/functions/geospatial.md)**
>
> H3 and spatial functions for points, coordinates and polygons.

## Statements and clauses

> **[Statements and clauses](https://docs.e6data.com/query/sql/functions/statements)**
>
> 3 pages. Statements and clauses that aren't functions: unloading results to object storage, grouping at several levels, and excluding columns or rows.


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