This is very real. Users post problems they experience with JSON fields, i.e.:

$conn = new Connection();
  $query = SphinxQL::create($conn)->select('product_id')->from('parameter_index');
  if (!empty($data['minCoast']) and !empty($data['maxCoast'] and ($data['minCoast'] <  $data['maxCoast']) )) {
  $query -> where('attr.coast', 'BETWEEN', [$data['minCoast'],$data['maxCoast']]);
}

if (!empty($data['catalog'])) {
  $query -> where('attr.catalog_id', '=', $data['catalog']);
}
$total = $query->execute();

It causes an error:

syntax error, unexpected $undefined, expecting IDENT (or 97 other tokens) near 'attr[coast]BETWEEN '1000' AND '7000' ANDattr[catalog_id]= '2'' [ SELECTproduct_idFROMparameter_indexWHEREattr[coast]BETWEEN '1000' AND '7000' ANDattr[catalog_id]` = '2']``

The matter is 'attr.catalog_id' and 'attr.coast' are JSON fields. A working request would be (note that backticks were partially removed):

attr["coast"] BETWEEN '1000' AND '7000' AND attr["catalog_id"] = '2'' [ SELECT product_idFROMparameter_index WHERE attr["coast"] BETWEEN '1000' AND '7000' AND attr["catalog_id"] = '2'

This is because Sphinx currently cannot parse JSON fields that are surrounded by backticks. MySQL wouldn't parse that syntax either, e.g. test.table surrounded with backticks wil end up with a syntax error.

I suggest removing backticks as a whole (Sphinx fields can't contain spaces anyway) or at least remove backticks from JSON fields.

Also I noticed that attr.catalog_id becomes attr[catalog_id] which is also wrong (not sure if it's Query builder or user's request though). The proper syntax would be either attr.catalog_id or attr["catalog_id"].