Imapala Regex - 查找特定的字符序列，它们之间有分隔符，有些不是字母、数字或下划线

Question

I am new to regex and need to search a string field in Impala for multiple matches to this exact sequence of characters: ~FC* followed by 11 more * that could have letters/digits between (but could not, they are basically delimiters in this string field). After the 12th * (if you count #1 in ~FC* ) it should be immediately followed by Y~ .

since the asterisks are not letters or digits, I am unsure on how to search for these delimiters properly.

This is my SQL so far:

select 
    regexp_extract(col_name, '(~FC\\*).*(\\*Y~)', 1) as "pattern_found"
from db.table
where id = 123456789
limit 1

data returned:

pattern_found
--------------
~FC*

(~FC\\*) in Impala SQL it returns ~FC* which is great (got it from my other question )

Been trying this (~FC\\*).*(\\*Y~) which obviously isnt counting the number of asterisks but its is also not picking the Y up.

This is a test string, it has 2 occurrences:

N4*CITY*STATE*2155446*2120~FC*C*IND*30*MC*blah blah fjdgfeufh*27*0*****Y~FC*Z*IND*39*MC*jhlkfhfudfgsdkufgkusgfn*23*0*****Y~

results should be these 2, which has an overlapping ~ between them. but will settle for at least the first being found if both cannot.

~FC*C*IND*30*MC*blah blah fjdgfeufh*27*0*****Y~ ~FC*Z*IND*39*MC*jhlkfhfudfgsdkufgkusgfn*23*0*****Y~

Answer 1

figured out a solution but happy to learn of a better way to accomplish this

This is what worked in Impala SQL, needed parentheses and double escape backslashes for allllll the asterisks:

(~FC\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*Y)

Full SQL:

select 
    regexp_extract(col_name, '(~FC\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*[^\\*]*\\*Y)', 1) as "pattern_found"
from db.table
where id = 123456789
limit 1

and here is the RegexDemo without the additional syntax needed for Impala SQL