I'm, trying to implement the feature I asked about here: www.joomlapolis.com/forum/153-professional-member-support/237151-beta-test-invites

but I'm getting this error message:

An error has occurred.

1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 2

when using this query cited in the tutorial:
SELECT * FROM `membercodes`
WHERE `code`='[value]' AND NOT EXISTS( SELECT * FROM `#__comprofiler` WHERE `cb_memberaccesscode`='[value]')


I'm on Joomla 3.7.5. MySQL version 5.6.36-82.1. Any ideas what might be wrong? I'm setting it exactly as in the tutorial. Thanks.

Never mind - solved it!
Big screen = small font + old, tire eyes = spelling error!