# Overview of *SelectFromCollection* transform
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Certain transforms have multiple datasets as their output instead of a single dataset, for example, *SplitFields*. The *SelectFromCollection* transform selects one dataset (`DynamicFrame`) from a collection of datasets (an array of `DynamicFrames`). The output for the transform is the selected `DynamicFrame`. 

You must use this transform after you use a transform that creates a collection of `DynamicFrames`, such as:
+ Custom code transforms
+ *SplitFields*

If you don't add a *SelectFromCollection* transform node to your job diagram after any of these transforms, you will get an error for your job. 

The parent node for this transform must be a node that returns a collection of `DynamicFrames`. If you choose a parent for this transform node that returns a single `DynamicFrame`, such as a *Join* transform, your job returns an error. 

Similarly, if you use a *SelectFromCollection* node in your job diagram as the parent for a transform that expects a single `DynamicFrame` as input, your job returns an error.

![\[The screenshot shows the Node parents field on the Node properties tab of the node details panel. The selected node parent is SplitFields and the error message displayed reads "Parent node Split Fields outputs a collection, but node Drop Fields does not accept a collection."\]](http://docs.aws.amazon.com/glue/latest/dg/images/screenshot-edit-splitfields-wrong-parent.png)