sentences splits a string into an array of sentences, where each sentence is an array of words. It's useful for text analysis tasks like counting sentences, extracting individual words, or preparing text for downstream NLP processing.

The levenshtein function computes the Levenshtein distance between two string columns — the minimum number of single-character edits (insertions, deletions, or substitutions) needed to transform one string into the other. It's useful for fuzzy matching, typo detection, and deduplication.

The soundex function returns the soundex code of a string column — a four-character phonetic encoding that groups similar-sounding names together. It's useful for fuzzy matching, deduplication, and search where exact spelling varies.

hex converts an integer or string column to its hexadecimal representation. unhex does the reverse — it decodes a hex string back to binary. These are useful when working with low-level data formats, color codes, or any system that uses hex encoding.

base64 encodes a binary or string column into a Base64-encoded string. unbase64 does the reverse — it decodes a Base64 string back into binary. Together they let you safely represent binary data as printable text, which is useful when passing data through systems that only handle strings.

The ascii function returns the numeric code point of the first character in a string column. The chr and char SQL functions do the reverse — they convert an integer code point back to a character. Together they let you move between characters and their numeric representations.

The reverse function reverses the character order of a string column. It also works on array columns, reversing the element order — but this article focuses on string usage.

The repeat function duplicates a string column a specified number of times. The space SQL function generates a string of spaces — it's shorthand for repeat(" ", n). Together they cover common needs like building separators, indenting text, and padding output.

replace substitutes all occurrences of a substring within a string column. It's the straightforward choice when you need a literal find-and-replace without regular expressions.

overlay replaces a portion of a string column starting at a given position with a replacement string. It works like the SQL standard OVERLAY function and is useful for masking, patching, or inserting text at a specific character position.