median function documentation, improve test

Author: gavinking

documentation/src/main/asciidoc/querylanguage/Relational.adoc

@@ -178,13 +178,17 @@ The standard aggregate functions defined in both ANSI SQL and JPQL are these one
 
 | `count()`, including `count(distinct)`, `count(all)`, and `count(*)` | Any | `Long` | ✔/✔
 | `avg()` | Any numeric type | `Double` | ✔/✔
+| `median()` | Any numeric type | `Double` | ✖/✖
 | `min()` | Any numeric type, or string | Same as the argument type | ✔/✔
 | `max()` | Any numeric type, or string | Same as the argument type | ✔/✔
 | `sum()` | Any numeric type | See table below | ✔/✔
 | `var_pop()`, `var_samp()` | Any numeric type | `Double` | ✖/✔
 | `stddev_pop()`, `stddev_samp()` | Any numeric type | `Double` | ✖/✔
 |===
 
+[NOTE]
+The `median()` function is not supported on MySQL or Sybase ASE.
+
 [[aggregate-functions-example]]
 [source, hql]
 [%unbreakable]

hibernate-core/src/main/java/org/hibernate/dialect/HSQLDialect.java

@@ -62,6 +62,9 @@
 
 /**
  * A {@linkplain Dialect SQL dialect} for HSQLDB (HyperSQL) 2.6.1 and above.
+ * <p>
+ * Please refer to the
+ * <a href="https://hsqldb.org/doc/2.0/guide/index.html">HyperSQL User Guide</a>.
  *
  * @author Christoph Sturm
  * @author Phillip Baird

hibernate-core/src/test/java/org/hibernate/orm/test/query/hql/FunctionTests.java

@@ -2316,6 +2316,12 @@ public void testFormatTime(SessionFactoryScope scope) {
 	public void testMedian(SessionFactoryScope scope) {
 		scope.inTransaction(
 				session -> {
+					assertEquals( 1.0,
+							session.createQuery("select median(e.theDouble) from EntityOfBasics e", Double.class).getSingleResult(),
+							1e-5);
+					assertEquals( 5.0,
+							session.createQuery("select median(e.theInt) from EntityOfBasics e", Double.class).getSingleResult(),
+							1e-5);
 					List<Object[]> list = session.createQuery("select median(e.theDouble), median(e.theInt) from EntityOfBasics e", Object[].class)
 							.list();
 					assertEquals( 1, list.size() );

hibernate-testing/src/main/java/org/hibernate/testing/orm/junit/DialectFeatureChecks.java

@@ -552,13 +552,11 @@ public boolean apply(Dialect dialect) {
 	public static class SupportsMedian implements DialectFeatureCheck {
 		public boolean apply(Dialect dialect) {
 			dialect = DialectDelegateWrapper.extractRealDialect( dialect );
-			return !( dialect instanceof MySQLDialect
+			return !( dialect instanceof MySQLDialect && !(dialect instanceof MariaDBDialect)
 					|| dialect instanceof SybaseDialect
 					|| dialect instanceof DerbyDialect
 					|| dialect instanceof FirebirdDialect
-					|| dialect instanceof DB2Dialect && ( (DB2Dialect) dialect ).getDB2Version().isBefore( 11 ) )
-					|| dialect instanceof InformixDialect
-					|| dialect instanceof MariaDBDialect;
+					|| dialect instanceof DB2Dialect && ( (DB2Dialect) dialect ).getDB2Version().isBefore( 11 ) );
 		}
 	}