Is your feature request related to a problem or challenge? Please describe what you are trying to do.

DataFusion supports many types of subqueries (originally tracked via #2248). This epic tracks additional features / support

See also the original design document.

• Implement physical plan for IN Subquery #1835
• Implement physical plan for EXISTS subquery #123
• [Feature] (All) logical optimizers should optimize subqueries #2480
• General framework to decorrelate the subqueries #5492
• Additional ideas for optimizing subqueries #5484
• Implement physical execution of uncorrelated scalar subqueries #3781
• Add support for wider range of scalar subqueries #3725
• Add support for scalar subqueries in BETWEEN expressions #3667
• scalar_subquery_to_join internal error #3417
• Validate subquery expressions #2361
• Add support for correlated subquery #6140
• decorrelate_where_in reports error when optimizing limit subquery #5808
• SQL case, This feature is not implemented: Physical plan does not support logical expression EXISTS (<subquery>) #5789
• Error when using DISTINCT in a filter clause using a subquery #5633
• Decorrelate scalar subqueries with more complex filter expressions #14554
• Nested correlated subquery error with a depth exceeding 1 #15558