I'd look at the field, check the model, check if their is metadata, etc., and see if it falls into a level.
我会查看这些字段,检查模型,检查它们是否拥有元数据等,并看它们是否可以属于某个级别。
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The combined record is much easier to use-you only have to check the PICTURE field to see if it's not null (which was the result of the LEFT OUTER JOIN).