which displays per-product sales totals in only the top sales regions. With clause defines two auxiliary statements named regional_transformation and top_regions, where the output of regional_conversion is used in top_nations and the output of top_places is used in the priple could have been written without With, but we’d have needed two levels of nested sub-Discovers.
not, tend to a routine doesn’t require productivity rows that are totally duplicate: it may be must look at just one or a few industries to find out if a comparable point has been reached before
optional RECURSIVE modifier changes That have from a mere syntactic convenience into a feature that accomplishes things not otherwise possible in standard SQL. Using RECURSIVE, a With query can refer to its own output. A very simple example is this query to sum the integers from 1 through 100:
general form of a recursive Which have query is always a non-recursive term, then Partnership (or Union All of the), then a recursive term, where only the recursive term can contain a reference to the query’s own output.
