When I'm typing in the WQS query form, help is provided in terms of variable names and such, but if I'm typing a SPARQL command like "SHA512", "group_concat", "FILTER" or "BIND" or even just an asterisk, no help is available as to how this command can or should be used (nor can I search for example queries using that command - see T154768).
It would be very useful to have some sort of help structure that makes users aware of SPARQL syntax, including parentheses, curly brackets and things like ";.:!*/+" or Wikidata specifics like "wdt:", "p:", "pq", "psv", "wdno" etc.
This help could become available either
- as characters are being typed in or
- by clicking on/ hovering over characters that are already there (e.g. in an example query) or
- statically from a list of supported commands/ operators/ namespaces etc. that are generally available for such a query (similar to the special characters list in edit mode on many wikis), though this could perhaps be limited to things not yet used in a given query if help for the used ones is already there as per the two bullets above.
Besides syntax info, the help could also include some tips for query optimization.