Add SPLIT(STRING) support in SQL & Table API

SPLIT Function

Description
Splits a string into an array of substrings, based on a delimiter.

Syntax
The syntax for the SPLIT function is:

SPLIT(col1, delimiter)

Splits a string into an array of substrings based on a delimiter. If the delimiter is not found, then the original string is returned as the only element in the array. If the delimiter is empty, then all characters in the string are split. If either, string or delimiter, are NULL, then a NULL value is returned.

If the delimiter is found at the beginning or end of the string, or there are contiguous delimiters, then an empty space is added to the array.

Example
Let's look at some  function examples and explore how to use the SPLIT function.

For example:

SELECT SPLIT('abcdefg', 'c');
Result: ['ab', 'defg']

see also:

1. ksqlDB Split function

ksqlDB provides a scalar function named SPLIT which splits a string into an array of substrings based on a delimiter.

Syntax: SPLIT(string, delimiter)

For example: SPLIT('a,b,c', ',') will return ['a', 'b', 'c'].

https://docs.ksqldb.io/en/0.8.1-ksqldb/developer-guide/ksqldb-reference/scalar-functions/#split

2. Apache Hive Split function

Hive offers a function named split which splits a string around a specified delimiter and returns an array of strings.

Syntax: array<string> split(string str, string pat)

For example: split('a,b,c', ',') will return ["a", "b", "c"].

https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF

3. Spark SQL Split function

Spark SQL also offers a function named split, similar to the one in Hive.

Syntax: split(str, pattern[, limit])

Here, limit is an optional parameter to specify the maximum length of the returned array.

For example: split('oneAtwoBthreeC', '[ABC]', 2) will return ["one", "twoBthreeC"].

https://spark.apache.org/docs/latest/api/sql/index.html#split

4. Presto Split function

Presto offers a function named split which splits a string around a regular expression and returns an array of strings.

Syntax: array<varchar> split(string str, string regex)

For example: split('a.b.c', '\.') will return ["a", "b", "c"].

https://prestodb.io/docs/current/functions/string.html