Question

i need to export a MySql Database to a SQLite database, im getting only the needed data from medias to make de SQLite database smaller as posible.

I have a Query that give to me only the animalsMedias or the plantsMedias that are related to the entry with the last version, published and not filed of an animal or a plant.

SELECT AM.*, max(A.version) AS version FROM animalsMedias AS AM INNER JOIN animals
AS A ON(AM.idAnimal = A.idAnimal AND A.filed = 0 AND A.published = 1) GROUP BY 
A.idLanguaje, A.idVersion;

And to get only the medias related i try to make a SELECT on “medias” table that only returns to me the medias that are related with the result of the previous select, so i put both in “IN()”, but im getting the error:

#1241 - Operand should contain 1 column(s)

That is the query:

SELECT * from medias 
WHERE idMedia IN(SELECT AM.*, max(A.version) AS version FROM
animalsMedias AS AM 
INNER JOIN animals AS A ON(AM.idAnimal = A.idAnimal AND A.filed = 0 
AND A.published = 1) 
GROUP BY A.idLanguaje, A.idVersion) 
OR idMedia IN(SELECT PM.*, max(P.version) AS version FROM plantsMedias AS PM 
INNER JOIN plants AS P ON(PM.idPlant = P.idPlant AND P.filed = 0 AND P.published = 1) 
GROUP BY P.idLanguaje, P.idVersion);

How can i get the “max(A.version)” if i must use only 1 operand?, if i understood good, inside IN i must have only “IN(SELECT AM.idMedia FROM….” to be correct.

Thanks in advice and sorry for my english, i try my best.

Answer 1

JOIN the tables instead of these IN predicates:

SELECT 
  ....
  A.version AVersion,
  P.Version PVersion
FROM medias m
INNER JOIN animalsMedias AS AM  ON m.idMedia = am.Id
INNER JOIN plantsMedias  AS PM  ON m.idMedia = PM.ID
LEFT JOIN
(
  SELECT idAnimal, max(A.version) AS version 
  FROM animals
  WHERE A.filed = 0 
    AND A.published = 1     
  GROUP BY A.idLanguaje, A.idVersion 
) AS  A  ON AM.idAnimal = A.idAnimal 
LEFT JOIN
(
  SELECT idPlant, MAX(Version) version
  FROM Plants
  WHERE field = 0 AND published = 1
  GROUP BY P.idLanguaje, P.idVersion
) AS p ON PM.idPlant = P.idPlant;