SQL query Binding to MySQL procedure with OUT parameters

In a MySQL database a procedure is defined as follows:

I have no problem to call it from a Python script.
If I play with that in a Power Table data SQL query binding like this:

I get no rows and the following error message instead:

Calling the procedure with in_action=6 should return a recordset of recipes.

I’m used to MS SQL Server stored procedures, where you have no OUT parameters and I cannot figure out what the problem is here. Any suggestion?

Thanks in advance, regards

Just to answer my post: I dropped the line:
set @out=0;
and it works. Can anyone explain me? Can’t you submit a whole sql batch to MySQL?

No. JDBC drivers take one and only one statement at a time. It’s not just MySQL. Running multiple statements is pretty much always a client-side operation for all brands, and JDBC just doesn’t offer the parsing for it.