Module expr_fn Copy item path Source ascii Returns the numeric code of the first character of the argument. bit_length Returns the number of bits in the string btrim Removes all characters, spaces by default, from both sides of a string chr Converts the Unicode code point to a UTF8 character concat Concatenates the text representations of all the arguments. NULL arguments are ignored concat_ws Concatenates all but the first argument, with separators. The first argument is used as the separator string, and should not be NULL. Other NULL arguments are ignored. contains Return true if search_string is found within string. ends_with Returns true if the string ends with the suffix, false otherwise. levenshtein Returns the Levenshtein distance between the two given strings lower Converts a string to lowercase. ltrim Removes all characters, spaces by default, from the beginning of a string octet_length returns the number of bytes of a string overlay replace the substring of string that starts at the start’th character and extends for count characters with new substring repeat Repeats the string to n times replace Replaces all occurrences of from with to in the string rtrim Removes all characters, spaces by default, from the end of a string split_part Splits a string based on a delimiter and picks out the desired field based on the index. starts_with Returns true if string starts with prefix. to_hex Converts an integer to a hexadecimal string. trim Removes all characters, spaces by default, from both sides of a string upper Converts a string to uppercase. uuid returns uuid v4 as a string value