问题
I'm trying to create a UNION query using the Propel ORM e.g
$criterion1 UNION $criterion2
Does anyone know how to do this?
回答1:
You cannot create a union query using Criteria. Instead, you can create the SQL string yourself, and use it to hydrate the objects. If you still want to use Criteria to build both parts of the union query, you can call BasePeer::createSelectSql(Criteria $criteria, array &$params). This will return an SQL string with ? in the places of the values that need to be set by the PDO layer. The second parameter is an array that will be filled with these parameters (which is why you pass it by reference). You can pass this to the PDOStatement::execute(array $params) function.
回答2:
Two solutions come to mind. Firstly, the trivial approach is to run two separate calls and then use array_merge to glue them together. Depending on your use-case, this may not be as time-expensive as you think.
Also, if you are stuck writing the query, write a view with the query you want, and then put that in your Propel model. I had a bunch of very complicated master-detail screens in Propel/symfony 1.x, and this approach worked a treat. It does go slightly against the philosophy of using an ORM, but hey, it's fun to break the rules once in a while! :)
来源：https://stackoverflow.com/questions/1985646/union-query-with-propel-orm