How to write regular expression for query string ?operation= or &test=do

[wadibmi]

We want to raise a threat protection error if the query string has ?operation= or . I tried adding below expressions but it was not working since the space between = and or was considering as @20 in apigee. 

1. <Variable name="request.querystring">
<Pattern ignoreCase="true">[\s]*((\bexec\b)|(\bdrop\b)|(\binsert\b)|(\bdelete\b)|(\bshutdown\b)|(\bupdate\b)|(\s\bor\b\s))</Pattern>
</Variable>

2. <Variable name="request.querystring">
<Pattern ignoreCase="true">[\s]*((\bexec\b)|(\bdrop\b)|(\binsert\b)|(\bdelete\b)|(\bshutdown\b)|(\bupdate\b)|(\sor\s))</Pattern>
</Variable>

Kindly let me know for the same.