So, @rotnroll666 nerd sniped me again. Apparently, the Neo4j Cypher query language supports arbitrary reductions, just like any functional collection API, oh say, the JDK Stream API: Stream.of(2, 4, 3, 1, 6, 5) .reduce((i, j) -> i * j) .ifPresent(System.out::println); // Prints 720 SQL doesn't have this, yet it would be very useful to be … Continue reading Implementing a generic REDUCE aggregate function with SQL
Tag: Custom Aggregate Function
Writing Custom Aggregate Functions in SQL Just Like a Java 8 Stream Collector
All SQL databases support the standard aggregate functions COUNT(), SUM(), AVG(), MIN(), MAX(). Some databases support other aggregate functions, like: EVERY() STDDEV_POP() STDDEV_SAMP() VAR_POP() VAR_SAMP() ARRAY_AGG() STRING_AGG() But what if you want to roll your own? Java 8 Stream Collector When using Java 8 streams, we can easily roll our own aggregate function (i.e. a … Continue reading Writing Custom Aggregate Functions in SQL Just Like a Java 8 Stream Collector