Thanks Bucklash, your version don't work. No Klas, there is nothing wrong with my query or my data.
Working on localhost, I have compared the working of select dynamic in several versions of Joomla and Seblod. Select dynamic works fine in Joomla 3.6.5 and 3.7.0 untill Seblod 3.11. When I replace select_dynamic.php in Seblod 3.11 by the version of that file in Seblod 3.10, my queries work again.This hack works in Joomla 3.8.1 and Seblod 3.15 to.
I located your problem, you are not using AS text and AS value in your query. For security purposes variables passed to search query get checked against all possible values from select and if you are not using AS value none will match.
Klas, thank you for your efforts to resolve the problem. The use of aliases is not mandatory in MYSQL. What you say about this is already mentioned in the help for Seblod v2.x. My queries work well because the drop-lists are formed, but the selection of an option has no effect if I use select_dynamic.php v3.11 and later, with v3.10 and earlier it works.
To find out the origin of the problem, I've compared in Winmerge the versions 3.10 and 3.11 of select_dynamic.php. The code in line number 469 - 498 of version 3.10 is almost equal to the code in line number 494 - 520 of version 3.11. The difference is the line with "$field->value = $value;", which occurs in version 3.10 and not in version 3.11. I inserted this code on line 514 in version 3.11 and now this version is also working fine. So the error has not been made by me, but at the change of select_dynamic.php version 3.10 to version 3.11.