I have this formula on my adhoc search, but it’s not working and throws an error I tried also using double quotes outside and inner as single but still the same issue And from the below i tried to escape it

CASE WHEN {item.custitem_size} = 'XS' OR {item.custitem_size} = 'X-Small' OR {item.custitem_size} = 'Men\'s XS' OR {item.custitem_size} = 'Women\'s XS' THEN {quantity} ELSE 0 END

I believe you escape a single quote by just adding a second single quote:

'Women''s XS'

Thanks @erictgrubaugh! This worked.