Flink rookie here, but I've used ksqlDB a fair bit. Does Flink's SQL DML support operations on streams/topics, or just tables? It appears from the docs that the SQL language only works on tables. Specifically I'm looking to use SQL statements to express stream filtering, splits and stream-stream and stream-table joins.

Flink doesn't distinguish between streams/tables like ksqlDB does: everything in Flink is a "table". See https://nightlies.apache.org/flink/flink-docs-master/docs/dev/table/concepts/dynamic_tables/ for some more details. A table can defined over a Kafka topic, a Postgress table, a file on S3 etc.

Ah, perfect! Thanks so much for the pointer.