Oracle has cursor expressions that returns a resultset inside a cell from the parent resultset. The whole resultset could then be serialized to json, xml or whatever<p>I wish there was an equivalent function in PostgreSQL. I've even asked a question about that on stackoverflow:<p><a href="https://stackoverflow.com/questions/8637050/cursor-inside-sql-query" rel="nofollow">https://stackoverflow.com/questions/8637050/cursor-inside-sq...</a>