Mysql : Not allowed to return a result set from a function

Question

I have write one function but getting this error Not allowed to return a result set from a function

DEL         


        

Answer 1

You want to assign the result of a query to a variable, but in fact you're just selecting. That's why MySQL's complaining.

You have to change this

            SELECT  p_KeyValue = ListName + '.' + Value
            FROM ListsTable
            WHERE EntryID = p_ParentID  LIMIT 1 ;

to

            SELECT CONCAT(ListName, '.', `Value`)
            INTO p_KeyValue
            FROM ListsTable
            WHERE EntryID = p_ParentID  LIMIT 1 ;

And you should add an ORDER BY. A LIMIT without ORDER BY doesn't make sense, since there's no guaranteed order in a relational database.