在SQL中整个列的两个定界符之间提取值

Question

I am looking for a way to extract all substrings between two delimiters over an entire column.I have found ways to do this for each string separately, but I need something I can apply over the entire column.

For example if I have a column called "NAMES" that contains the below values:

• 1235_brandon_098410090
• 1242353_sam_1920420101222
• 134214_kristein_39402384

I want my output to be

• brandon
• sam
• kristein

how do I do this?

I've tried this: regex_substr(names,'_(.*?)_'

Query Error: error: function regex_substr(character varying, unknown) does not exist

Answer 1

In MySQL, I think you can use substring_index() :

select substring_index(substring_index(names, '_', 2), '_', -1)

This extracts the second value delimited by underscores, which is what all the sample data suggests is needed.

EDIT:

Your error message looks like Postgres. This is the equivalent in Postgres:

select v.*, split_part(names, '_', 2)
from (values ('1242353_sam_1920420101222')) v(names);

In Postgres, you can use substring() with a pattern as well:

select v.*, substring(names from '[A-Za-z]+')