I have a custom text field called Revision (single line text). I can't seem to create a query to capture issues where Revision is (-), the initial rev for an item. All three characters are special characters... but I try Revision ~ \\(\\-\\) and the search bar says it can't find that JQL function. Other things I've tried:
\(\-\)
"\(\-\)"
'\(\-\)'
"\\(\\-\\)"
'\\(\\-\\)'
'\\-'
"\\-"
\\-
\u0028\u002D\u0029
\u0028
etc.
EDIT: I found a decent, albeit clumsy, workaround for this. With the SQL+JQL plugin, I can construct a SQL query to embed within JQL that does successfully match all characters, including special characters.