# Presto 316 Documentation

## 7.25. Teradata Functions

These functions provide compatibility with Teradata SQL.

## String Functions

`char2hexint`(string) → varchar

  Returns the hexadecimal representation of the UTF-16BE encoding of the string.

`index`(string, substring) → bigint

  Alias for `strpos()` function.

`substring`(string, start) → varchar

  Alias for `substr()` function.

`substring`(string, start, length) → varchar

  Alias for `substr()` function.

## Date Functions

The functions in this section use a format string that is compatible with the Teradata datetime functions. The following table, based on the Teradata reference manual, describes the supported format specifiers:

Specifier | Description
--- | ---
`- / , . ; :` | Punctuation characters are ignored
`dd` | Day of month (1-31)
`hh` | Hour of day (1-12)
`hh24` | Hour of the day (0-23)
`mi` | Minute (0-59)
`mm` | Month (01-12)
`ss` | Second (0-59)
`yyyy` | 4-digit year
`yy` | 2-digit year

Warning

Case insensitivity is not currently supported. All specifiers must be lowercase.

`to_char`(timestamp, format) → varchar

  Formats `timestamp` as a string using `format`.

`to_timestamp`(string, format) → timestamp

  Parses `string` into a `TIMESTAMP` using `format`.

`to_date`(string, format) → date

  Parses `string` into a `DATE` using `format`.