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~
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
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