HHH-15516 add two-arg form of log() to HQL

documentation/src/main/asciidoc/userguide/chapters/query/hql/QueryLanguage.adoc

@@ -1023,6 +1023,7 @@ Next, functions for working with numeric values:
 | `power()` | Exponentiation | `power(x,y)` | Universal in SQL dialects
 | `ln()` | Natural logarithm | `ln(x)` | Very common in SQL dialects
 | `log10()` | Base-10 logarithm | `log10(x)` | Very common in SQL dialects
+| `log()` | Arbitrary-base logarithm | `log(b,x)` | Very common in SQL dialects
 | `pi` | π | `pi` | Very common in SQL dialects
 | `sin()`, `cos()`, `tan()`, `asin()`, `acos()`, `atan()`, `atan2()` | Basic trigonometric functions | `sin(theta)`, `cos(theta)`, `atan2(opposite, adjacent)` | Very common in SQL dialects
 | `round()` | Numeric rounding | As usual: `round(number, places)` | Very common in SQL dialects

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

@@ -127,8 +127,8 @@ public abstract class AbstractTransactSQLDialect extends Dialect {
 
 		CommonFunctionFactory functionFactory = new CommonFunctionFactory(queryEngine);
 		functionFactory.cot();
-		functionFactory.log();
 		functionFactory.ln_log();
+		functionFactory.log_loglog();
 		functionFactory.log10();
 		functionFactory.atan2_atn2();
 		functionFactory.mod_operator();

hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java

@@ -207,7 +207,6 @@ public class DB2Dialect extends Dialect {
 
 		functionFactory.cot();
 		functionFactory.degrees();
-		functionFactory.log();
 		functionFactory.log10();
 		functionFactory.radians();
 		functionFactory.rand();

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

@@ -735,6 +735,7 @@ public abstract class Dialect implements ConversionContext {
 	 * <ul>
 	 * <li> <code>pi</code>
 	 * <li> <code>log10(arg)</code>
+	 * <li> <code>log(base, arg)</code>
 	 * <li> <code>sign(arg)</code>
 	 * <li> <code>sin(arg)</code>
 	 * <li> <code>cos(arg)</code>
@@ -817,6 +818,10 @@ public abstract class Dialect implements ConversionContext {
 
 		functionFactory.pi_acos();
 
+		//log(base, arg) supported on most databases, but emulate it here
+
+		functionFactory.log_ln();
+
 		//coalesce() function, supported by most databases, must be emulated
 		//in terms of nvl() for platforms which don't support it natively
 

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

@@ -444,7 +444,6 @@ public class MySQLDialect extends Dialect {
 		functionFactory.log();
 		functionFactory.log2();
 		functionFactory.log10();
-		functionFactory.pi();
 		functionFactory.trim2();
 		functionFactory.octetLength();
 		functionFactory.reverse();
@@ -498,6 +497,12 @@ public class MySQLDialect extends Dialect {
 				.setUseParenthesesWhenNoArgs( false )
 				.register();
 
+		queryEngine.getSqmFunctionRegistry().patternDescriptorBuilder( "pi", "cast(pi() as double)" )
+				.setInvariantType(basicTypeRegistry.resolve( StandardBasicTypes.DOUBLE ))
+				.setExactArgumentCount(0)
+				.setArgumentListSignature("")
+				.register();
+
 		// MySQL timestamp type defaults to precision 0 (seconds) but
 		// we want the standard default precision of 6 (microseconds)
 		functionFactory.sysdateExplicitMicros();

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

@@ -265,6 +265,8 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
 		// AVG by default uses the input type, so we possibly need to cast the argument type, hence a special function
 		functionFactory.avg_castingNonDoubleArguments( this, SqlAstNodeRenderingMode.DEFAULT );
 
+		functionFactory.log_log();
+
 		functionFactory.truncate_round();
 		functionFactory.everyAny_minMaxIif();
 		functionFactory.octetLength_pattern( "datalength(?1)" );

hibernate-core/src/main/java/org/hibernate/dialect/function/CommonFunctionFactory.java

@@ -88,6 +88,9 @@ public class CommonFunctionFactory {
 				.register();
 	}
 
+	/**
+	 * For databases where the first parameter is the base
+	 */
 	public void log() {
 		functionRegistry.namedDescriptorBuilder( "log" )
 				.setArgumentCountBetween( 1, 2 )
@@ -96,6 +99,42 @@ public class CommonFunctionFactory {
 				.register();
 	}
 
+	public void log_ln() {
+		functionRegistry.patternDescriptorBuilder( "log", "ln(?2)/ln(?1)" )
+				.setExactArgumentCount( 2 )
+				.setParameterTypes(NUMERIC, NUMERIC)
+				.setInvariantType(doubleType)
+				.setArgumentListSignature("(NUMERIC base, NUMERIC arg)")
+				.register();
+	}
+
+	/**
+	 * SQL Server defines parameters in reverse order
+	 */
+	public void log_log() {
+		functionRegistry.patternDescriptorBuilder( "log", "log(?2,?1)" )
+				.setExactArgumentCount( 2 )
+				.setParameterTypes(NUMERIC, NUMERIC)
+				.setInvariantType(doubleType)
+				.setArgumentListSignature("(NUMERIC base, NUMERIC arg)")
+				.register();
+	}
+
+	/**
+	 * For Sybase
+	 */
+	public void log_loglog() {
+		functionRegistry.patternDescriptorBuilder( "log", "log(?2)/log(?1)" )
+				.setExactArgumentCount( 2 )
+				.setParameterTypes(NUMERIC, NUMERIC)
+				.setInvariantType(doubleType)
+				.setArgumentListSignature("(NUMERIC base, NUMERIC arg)")
+				.register();
+	}
+
+	/**
+	 * For SQL Server and Sybase
+	 */
 	public void ln_log() {
 		functionRegistry.namedDescriptorBuilder( "ln", "log" )
 				.setInvariantType(doubleType)
@@ -385,6 +424,7 @@ public class CommonFunctionFactory {
 		functionRegistry.noArgsBuilder( "pi" )
 				.setInvariantType(doubleType)
 				.setUseParenthesesWhenNoArgs( true )
+				.setArgumentListSignature("")
 				.register();
 	}
 
@@ -392,6 +432,7 @@ public class CommonFunctionFactory {
 		functionRegistry.patternDescriptorBuilder( "pi", "acos(-1)" )
 				.setInvariantType(doubleType)
 				.setExactArgumentCount(0)
+				.setArgumentListSignature("")
 				.register();
 	}
 

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

@@ -12,6 +12,7 @@ import java.sql.Timestamp;
 import java.time.LocalDate;
 import java.time.LocalTime;
 
+import org.hamcrest.number.IsCloseTo;
 import org.hibernate.testing.orm.domain.StandardDomainModel;
 import org.hibernate.testing.orm.domain.gambit.EntityOfBasics;
 import org.hibernate.testing.orm.junit.DialectFeatureChecks;
@@ -913,8 +914,24 @@ public class StandardFunctionTests {
 		scope.inTransaction(
 				session -> {
 					assertThat(
-						session.createQuery("select pi").getSingleResult(),
-							is( Math.PI )
+							session.createQuery("select pi", Double.class).getSingleResult(),
+							IsCloseTo.closeTo( Math.PI, 1e-9 )
+					);
+				}
+		);
+	}
+
+	@Test
+	public void testLog(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					assertThat(
+							session.createQuery("select log(3,9)", Double.class).getSingleResult(),
+							IsCloseTo.closeTo( 2d, 1e-9 )
+					);
+					assertThat(
+							session.createQuery("select log(10,1e12)", Double.class).getSingleResult(),
+							IsCloseTo.closeTo( 12d, 1e-9 )
 					);
 				}
 		);