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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Cannot combine 'order' and 'filters' in same query ","articleBody":"I am trying to query comments that belong to a story.\n\n``` python\nquery = datastore.Query(kind='Comment', filters=[('storyid', '=', 12345)], order=['timestamp'])\n```\n\nThis code breaks with to following error (I also have additional internal debug info I can share):\n\n``` python\ngcloud.exceptions.PreconditionFailed: 412 no matching index found.\n```\n\nTrying to debug this, I found the following work with no problems:\n\nRemoving order\n\n``` python\nquery = datastore.Query(kind='Comment', filters=[('storyid', '=', 12345)])\n```\n\nRemoving filters\n\n``` python\nquery = datastore.Query(kind='Comment', order=['timestamp'])\n```\n\nChanging order to use storyid\n\n``` python\nquery = datastore.Query(kind='Comment', filters=[('storyid', '=', 12345)], order=['storyid'])\n```\n\nWhy is this happening? The fact that the bottom three queries work and to top one does not is very confusing. Nothing I saw in the documentation indicates that filters and order affect each other.\n","author":{"url":"https://github.com/thesandlord","@type":"Person","name":"thesandlord"},"datePublished":"2015-05-04T22:18:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/860/google-cloud-python/issues/860"}