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This documentation is for the unreleased development version of jOOQ. Click on the above version links to get this documentation for a supported version of jOOQ.
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
Two subselects of degree less than 22 that are combined by a set operator are required to be of the same degree and, in most databases, also of the same type. jOOQ 3.0's introduction of Typesafe Record[N] types helps compile-checking these constraints:
// Some sample SELECT statements Select<Record2<Integer, String>> s1 = select(BOOK.ID, BOOK.TITLE).from(BOOK); Select<Record1<Integer>> s2 = selectOne(); Select<Record2<Integer, Integer>> s3 = select(one(), zero()); Select<Record2<Integer, String>> s4 = select(one(), inline("abc")); // Let's try to combine them: s1.union(s2); // Doesn't compile because of a degree mismatch. Expected: Record2<...>, got: Record1<...> s1.union(s3); // Doesn't compile because of a type mismatch. Expected: <Integer, String>, got: <Integer, Integer> s1.union(s4); // OK. The two Record[N] types match