Sql 查询交叉变换还是 Pivot？

Question

I have this query for MySql database:

    SELECT
    pim_pimcore_database.object_query_RGL.rulecode AS "rulecode",
    pim_pimcore_database.object_query_RGL.DescrizioneRegola AS "rule_desc",
    pim_pimcore_database.object_relations_RGL.position AS "id",
    pim_pimcore_database.objects.o_classId,
    pim_pimcore_database.objects.o_key,
    pim_pimcore_database.object_collection_ruleIF_RGL.Operatore,
    pim_pimcore_database.object_collection_ruleIF_RGL.Concatenatore
    FROM
    pim_pimcore_database.object_query_RGL
    LEFT JOIN pim_pimcore_database.object_relations_RGL
    ON pim_pimcore_database.object_query_RGL.oo_id = 
    pim_pimcore_database.object_relations_RGL.src_id 
    LEFT JOIN pim_pimcore_database.objects
    ON pim_pimcore_database.object_relations_RGL.dest_id = pim_pimcore_database.objects.o_id 
    LEFT JOIN pim_pimcore_database.object_collection_ruleIF_RGL
    ON pim_pimcore_database.object_relations_RGL.position = 
    pim_pimcore_database.object_collection_ruleIF_RGL.`index`
    AND pim_pimcore_database.object_relations_RGL.src_id = 
    pim_pimcore_database.object_collection_ruleIF_RGL.o_id
    GROUP BY
    pim_pimcore_database.object_relations_RGL.position AS "ID"
    WHERE
    pim_pimcore_database.object_query_RGL.oo_id = 1042 AND 
    pim_pimcore_database.object_relations_RGL.ownername ="IfStatement"

That gives me the result:

But what I need is table like this:

How do I change the query for the desired output?

Answer 1

Your cartesian product (doubling of the rows) appears to come from joining pim_pimcore_database.objects on o_id.

If instead you represent this table twice in the query (join it twice) with relevant aliases and a predicate that selects only those kind of o_classid relevant to that alias, then the cartesian will disappear and you'll get the result you seek:

SELECT 
  ...,
  o_opt.key as OPT,
  o_com.key as COM,
  ...

LEFT JOIN pim_pimcore_database.objects o_opt ON ... AND o_opt.o_classid = 'OPT'
LEFT JOIN pim_pimcore_database.objects o_com ON ... AND o_com.o_classid = 'COM'