Question About query

[Arti Mattoo]

set @Provs: " "
SET @Provs=(CASE WHEN @Provs="" THEN "^" ELSE CONCAT('^',REPLACE(@Provs,"|","$|^"),"$") END);

Can anyone please explain whats the purpose of the metacharacters ^ $ in this query.

Thanks

[Steve R Jones]

A Google search shows me the following:

"^" - a caret is called an "anchoring operator," and matches the beginning of a string. The caret may also mean "not," which is at best confusing.
"$" - a dollar sign is another anchoring operator and matches only the end of a string.
"." - the period matches anything and is called the "match any character" operator. Many would call this a "wildcard" match character.
+ matches one or more repetitions of the preceding RE
* matches zero or more repetitions of the preceding RE
? matches zero or one repetition of the preceding RE


I would think the metacharacters are universal.

[Arti Mattoo]

Thankyou Steve for your quick respnse !!

I am still not able to understand how the case statement is running in this statement. Any help in understanding this would be really helpul

If
set @Provs: 'A|B|C'
SET @Provs=(CASE WHEN @Provs=" " THEN "^" ELSE CONCAT('^',REPLACE(@Provs,"|","$|^"),"$") END);

If the variable has been set to A|B|C then how would the statement run.