HHH-18497 Add xmlpi function

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

@@ -2175,6 +2175,7 @@ it is necessary to enable the `hibernate.query.hql.xml_functions_enabled` config
 | `xmlcomment()` | Constructs an XML comment from the single argument
 | `xmlforest()` | Constructs an XML forest from the arguments
 | `xmlconcat()` | Concatenates multiple XML fragments to each other
+| `xmlpi()` | Constructs an XML processing instruction
 |===
 
 
@@ -2266,6 +2267,39 @@ include::{xml-example-dir-hql}/XmlConcatTest.java[tags=hql-xmlconcat-example]
 
 WARNING: SAP HANA, MySQL, MariaDB and HSQLDB do not support this function.
 
+[[hql-xmlpi-function]]
+===== `xmlpi()`
+
+Constructs an XML processing instruction from the arguments.
+
+[[hql-xmlpi-bnf]]
+[source, antlrv4, indent=0]
+----
+include::{extrasdir}/xmlpi_bnf.txt[]
+----
+
+The identifier represents the XML processing instruction name and can be quoted by using backticks.
+
+[[hql-xmlpi-example]]
+====
+[source, java, indent=0]
+----
+include::{xml-example-dir-hql}/XmlPiTest.java[tags=hql-xmlpi-example]
+----
+====
+
+The optional second argument represents the processing instruction content.
+
+[[hql-xmlpi-content-example]]
+====
+[source, java, indent=0]
+----
+include::{xml-example-dir-hql}/XmlPiTest.java[tags=hql-xmlpi-content-example]
+----
+====
+
+WARNING: SAP HANA, MySQL, MariaDB and HSQLDB do not support this function.
+
 [[hql-user-defined-functions]]
 ==== Native and user-defined functions
 

documentation/src/main/asciidoc/userguide/chapters/query/hql/extras/xmlpi_bnf.txt

@@ -0,0 +1 @@
+"xmlpi(name " identifier ("," expressionOrPredicate)? ")"

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/DB2LegacyDialect.java

@@ -445,6 +445,7 @@ public class DB2LegacyDialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 	}
 
 	@Override

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/H2LegacyDialect.java

@@ -422,6 +422,7 @@ public class H2LegacyDialect extends Dialect {
 			functionFactory.xmlcomment();
 			functionFactory.xmlforest_h2();
 			functionFactory.xmlconcat_h2();
+			functionFactory.xmlpi_h2();
 		}
 		else {
 			functionFactory.listagg_groupConcat();

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/OracleLegacyDialect.java

@@ -330,6 +330,7 @@ public class OracleLegacyDialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 	}
 
 	@Override

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/PostgreSQLLegacyDialect.java

@@ -673,6 +673,7 @@ public class PostgreSQLLegacyDialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 
 		if ( getVersion().isSameOrAfter( 9, 4 ) ) {
 			functionFactory.makeDateTimeTimestamp();

hibernate-community-dialects/src/main/java/org/hibernate/community/dialect/SQLServerLegacyDialect.java

@@ -417,6 +417,7 @@ public class SQLServerLegacyDialect extends AbstractTransactSQLDialect {
 		functionFactory.xmlcomment_sqlserver();
 		functionFactory.xmlforest_sqlserver();
 		functionFactory.xmlconcat_sqlserver();
+		functionFactory.xmlpi_sqlserver();
 		if ( getVersion().isSameOrAfter( 14 ) ) {
 			functionFactory.listagg_stringAggWithinGroup( "varchar(max)" );
 			functionFactory.jsonArrayAgg_sqlserver( getVersion().isSameOrAfter( 16 ) );

hibernate-core/src/main/antlr/org/hibernate/grammars/hql/HqlLexer.g4

@@ -333,6 +333,7 @@ WRAPPER				: [wW] [rR] [aA] [pP] [pP] [eE] [rR];
 XMLATTRIBUTES		: [xX] [mM] [lL] [aA] [tT] [tT] [rR] [iI] [bB] [uU] [tT] [eE] [sS];
 XMLELEMENT			: [xX] [mM] [lL] [eE] [lL] [eE] [mM] [eE] [nN] [tT];
 XMLFOREST			: [xX] [mM] [lL] [fF] [oO] [rR] [eE] [sS] [tT];
+XMLPI				: [xX] [mM] [lL] [pP] [iI];
 YEAR				: [yY] [eE] [aA] [rR];
 ZONED				: [zZ] [oO] [nN] [eE] [dD];
 

hibernate-core/src/main/antlr/org/hibernate/grammars/hql/HqlParser.g4

@@ -1720,6 +1720,7 @@ jsonUniqueKeysClause
 xmlFunction
 	: xmlelementFunction
 	| xmlforestFunction
+	| xmlpiFunction
 	;
 
 /**
@@ -1743,6 +1744,13 @@ xmlforestFunction
 	: XMLFOREST LEFT_PAREN expressionOrPredicate (AS identifier)? (COMMA expressionOrPredicate (AS identifier)?)* RIGHT_PAREN
 	;
 
+/**
+ * The 'xmlpi()' function
+ */
+xmlpiFunction
+	: XMLPI LEFT_PAREN NAME identifier (COMMA expression)? RIGHT_PAREN
+	;
+
 /**
  * Support for "soft" keywords which may be used as identifiers
  *
@@ -1952,6 +1960,7 @@ xmlforestFunction
 	| XMLATTRIBUTES
 	| XMLELEMENT
 	| XMLFOREST
+	| XMLPI
 	| YEAR
 	| ZONED) {
 		logUseOfReservedWordAsIdentifier( getCurrentToken() );

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

@@ -430,6 +430,7 @@ public class DB2Dialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/dialect/H2Dialect.java

@@ -357,6 +357,7 @@ public class H2Dialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest_h2();
 		functionFactory.xmlconcat_h2();
+		functionFactory.xmlpi_h2();
 	}
 
 	/**

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

@@ -420,6 +420,7 @@ public class OracleDialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 	}
 
 	@Override

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

@@ -634,6 +634,7 @@ public class PostgreSQLDialect extends Dialect {
 		functionFactory.xmlcomment();
 		functionFactory.xmlforest();
 		functionFactory.xmlconcat();
+		functionFactory.xmlpi();
 
 		functionFactory.makeDateTimeTimestamp();
 		// Note that PostgreSQL doesn't support the OVER clause for ordered set-aggregate functions

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

@@ -435,6 +435,7 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
 		functionFactory.xmlcomment_sqlserver();
 		functionFactory.xmlforest_sqlserver();
 		functionFactory.xmlconcat_sqlserver();
+		functionFactory.xmlpi_sqlserver();
 		if ( getVersion().isSameOrAfter( 14 ) ) {
 			functionFactory.listagg_stringAggWithinGroup( "varchar(max)" );
 			functionFactory.jsonArrayAgg_sqlserver( getVersion().isSameOrAfter( 16 ) );

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

@@ -156,12 +156,15 @@ import org.hibernate.dialect.function.json.SQLServerJsonValueFunction;
 import org.hibernate.dialect.function.xml.H2XmlConcatFunction;
 import org.hibernate.dialect.function.xml.H2XmlElementFunction;
 import org.hibernate.dialect.function.xml.H2XmlForestFunction;
+import org.hibernate.dialect.function.xml.H2XmlPiFunction;
 import org.hibernate.dialect.function.xml.SQLServerXmlConcatFunction;
 import org.hibernate.dialect.function.xml.SQLServerXmlElementFunction;
 import org.hibernate.dialect.function.xml.SQLServerXmlForestFunction;
+import org.hibernate.dialect.function.xml.SQLServerXmlPiFunction;
 import org.hibernate.dialect.function.xml.XmlConcatFunction;
 import org.hibernate.dialect.function.xml.XmlElementFunction;
 import org.hibernate.dialect.function.xml.XmlForestFunction;
+import org.hibernate.dialect.function.xml.XmlPiFunction;
 import org.hibernate.query.sqm.function.SqmFunctionRegistry;
 import org.hibernate.query.sqm.produce.function.ArgumentTypesValidator;
 import org.hibernate.query.sqm.produce.function.FunctionParameterType;
@@ -4191,4 +4194,25 @@ public class CommonFunctionFactory {
 	public void xmlconcat_sqlserver() {
 		functionRegistry.register( "xmlconcat", new SQLServerXmlConcatFunction( typeConfiguration ) );
 	}
+
+	/**
+	 * Standard xmlpi() function
+	 */
+	public void xmlpi() {
+		functionRegistry.register( "xmlpi", new XmlPiFunction( typeConfiguration ) );
+	}
+
+	/**
+	 * H2 xmlpi() function
+	 */
+	public void xmlpi_h2() {
+		functionRegistry.register( "xmlpi", new H2XmlPiFunction( typeConfiguration ) );
+	}
+
+	/**
+	 * SQL Server xmlpi() function
+	 */
+	public void xmlpi_sqlserver() {
+		functionRegistry.register( "xmlpi", new SQLServerXmlPiFunction( typeConfiguration ) );
+	}
 }

hibernate-core/src/main/java/org/hibernate/dialect/function/xml/H2XmlPiFunction.java

@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.dialect.function.xml;
+
+import java.util.List;
+
+import org.hibernate.query.ReturnableType;
+import org.hibernate.sql.ast.SqlAstTranslator;
+import org.hibernate.sql.ast.spi.SqlAppender;
+import org.hibernate.sql.ast.tree.SqlAstNode;
+import org.hibernate.sql.ast.tree.expression.Literal;
+import org.hibernate.type.spi.TypeConfiguration;
+
+/**
+ * H2 xmlpi function.
+ */
+public class H2XmlPiFunction extends XmlPiFunction {
+
+	public H2XmlPiFunction(TypeConfiguration typeConfiguration) {
+		super( typeConfiguration );
+	}
+
+	@Override
+	public void render(
+			SqlAppender sqlAppender,
+			List<? extends SqlAstNode> sqlAstArguments,
+			ReturnableType<?> returnType,
+			SqlAstTranslator<?> walker) {
+		sqlAppender.appendSql( "'<?" );
+		final Literal literal = (Literal) sqlAstArguments.get( 0 );
+		sqlAppender.appendSql( (String) literal.getLiteralValue() );
+
+		if ( sqlAstArguments.size() > 1 ) {
+			sqlAppender.appendSql( " '||" );
+			sqlAstArguments.get( 1 ).accept( walker );
+			sqlAppender.appendSql( "||'?>'" );
+		}
+		else {
+			sqlAppender.appendSql( "?>'" );
+		}
+	}
+}

hibernate-core/src/main/java/org/hibernate/dialect/function/xml/SQLServerXmlPiFunction.java

@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.dialect.function.xml;
+
+import java.util.List;
+
+import org.hibernate.query.ReturnableType;
+import org.hibernate.sql.ast.SqlAstTranslator;
+import org.hibernate.sql.ast.spi.SqlAppender;
+import org.hibernate.sql.ast.tree.SqlAstNode;
+import org.hibernate.sql.ast.tree.expression.Literal;
+import org.hibernate.type.spi.TypeConfiguration;
+
+/**
+ * SQL Server xmlpi function.
+ */
+public class SQLServerXmlPiFunction extends XmlPiFunction {
+
+	public SQLServerXmlPiFunction(TypeConfiguration typeConfiguration) {
+		super( typeConfiguration );
+	}
+
+	@Override
+	public void render(
+			SqlAppender sqlAppender,
+			List<? extends SqlAstNode> sqlAstArguments,
+			ReturnableType<?> returnType,
+			SqlAstTranslator<?> walker) {
+		sqlAppender.appendSql( "cast('<?" );
+		final Literal literal = (Literal) sqlAstArguments.get( 0 );
+		sqlAppender.appendSql( (String) literal.getLiteralValue() );
+
+		if ( sqlAstArguments.size() > 1 ) {
+			sqlAppender.appendSql( " '+" );
+			sqlAstArguments.get( 1 ).accept( walker );
+			sqlAppender.appendSql( "+'?>'" );
+		}
+		else {
+			sqlAppender.appendSql( "?>'" );
+		}
+		sqlAppender.appendSql( " as xml)" );
+	}
+}

hibernate-core/src/main/java/org/hibernate/dialect/function/xml/XmlConcatFunction.java

@@ -22,7 +22,7 @@ import org.hibernate.type.spi.TypeConfiguration;
 import static org.hibernate.query.sqm.produce.function.FunctionParameterType.XML;
 
 /**
- * Standard XmlConcatFunction function.
+ * Standard xmlconcat function.
  */
 public class XmlConcatFunction extends AbstractSqmSelfRenderingFunctionDescriptor {
 
@@ -31,7 +31,7 @@ public class XmlConcatFunction extends AbstractSqmSelfRenderingFunctionDescripto
 				"xmlconcat",
 				FunctionKind.NORMAL,
 				StandardArgumentsValidators.composite(
-						new ArgumentTypesValidator( StandardArgumentsValidators.min( 1 ), XML )
+						new ArgumentTypesValidator( StandardArgumentsValidators.min( 2 ), XML )
 				),
 				StandardFunctionReturnTypeResolvers.invariant(
 						typeConfiguration.getBasicTypeRegistry().resolve( String.class, SqlTypes.SQLXML )

hibernate-core/src/main/java/org/hibernate/dialect/function/xml/XmlForestFunction.java

@@ -26,7 +26,7 @@ import static java.lang.Character.isLetter;
 import static java.lang.Character.isLetterOrDigit;
 
 /**
- * Standard XmlForestFunction function.
+ * Standard xmlforest function.
  */
 public class XmlForestFunction extends AbstractSqmSelfRenderingFunctionDescriptor {
 

hibernate-core/src/main/java/org/hibernate/dialect/function/xml/XmlPiFunction.java

@@ -0,0 +1,60 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.dialect.function.xml;
+
+import java.util.List;
+
+import org.hibernate.query.ReturnableType;
+import org.hibernate.query.sqm.function.AbstractSqmSelfRenderingFunctionDescriptor;
+import org.hibernate.query.sqm.function.FunctionKind;
+import org.hibernate.query.sqm.produce.function.ArgumentTypesValidator;
+import org.hibernate.query.sqm.produce.function.StandardArgumentsValidators;
+import org.hibernate.query.sqm.produce.function.StandardFunctionArgumentTypeResolvers;
+import org.hibernate.query.sqm.produce.function.StandardFunctionReturnTypeResolvers;
+import org.hibernate.sql.ast.SqlAstTranslator;
+import org.hibernate.sql.ast.spi.SqlAppender;
+import org.hibernate.sql.ast.tree.SqlAstNode;
+import org.hibernate.sql.ast.tree.expression.Literal;
+import org.hibernate.type.SqlTypes;
+import org.hibernate.type.spi.TypeConfiguration;
+
+import static org.hibernate.query.sqm.produce.function.FunctionParameterType.ANY;
+import static org.hibernate.query.sqm.produce.function.FunctionParameterType.STRING;
+
+/**
+ * Standard xmlpi function.
+ */
+public class XmlPiFunction extends AbstractSqmSelfRenderingFunctionDescriptor {
+
+	public XmlPiFunction(TypeConfiguration typeConfiguration) {
+		super(
+				"xmlpi",
+				FunctionKind.NORMAL,
+				StandardArgumentsValidators.composite(
+						new ArgumentTypesValidator( StandardArgumentsValidators.between( 1, 2 ), STRING, STRING )
+				),
+				StandardFunctionReturnTypeResolvers.invariant(
+						typeConfiguration.getBasicTypeRegistry().resolve( String.class, SqlTypes.SQLXML )
+				),
+				StandardFunctionArgumentTypeResolvers.invariant( typeConfiguration, ANY, STRING )
+		);
+	}
+
+	@Override
+	public void render(
+			SqlAppender sqlAppender,
+			List<? extends SqlAstNode> sqlAstArguments,
+			ReturnableType<?> returnType,
+			SqlAstTranslator<?> walker) {
+		sqlAppender.appendSql( "xmlpi(name " );
+		final Literal literal = (Literal) sqlAstArguments.get( 0 );
+		sqlAppender.appendDoubleQuoteEscapedString( (String) literal.getLiteralValue() );
+		if ( sqlAstArguments.size() > 1 ) {
+			sqlAppender.appendSql( ',' );
+			sqlAstArguments.get( 1 ).accept( walker );
+		}
+		sqlAppender.appendSql( ')' );
+	}
+}

hibernate-core/src/main/java/org/hibernate/query/criteria/HibernateCriteriaBuilder.java

@@ -4097,6 +4097,22 @@ public interface HibernateCriteriaBuilder extends CriteriaBuilder {
 	@Incubating
 	JpaExpression<String> xmlconcat(List<? extends Expression<?>> elements);
 
+	/**
+	 * Creates an XML processing with the given name.
+	 *
+	 * @since 7.0
+	 */
+	@Incubating
+	JpaExpression<String> xmlpi(String elementName);
+
+	/**
+	 * Creates an XML processing with the given name and content.
+	 *
+	 * @since 7.0
+	 */
+	@Incubating
+	JpaExpression<String> xmlpi(String elementName, Expression<String> content);
+
 	/**
 	 * Creates a named expression. The name is important for the result of the expression,
 	 * e.g. when building an {@code xmlforest}, the name acts as the XML element name.

hibernate-core/src/main/java/org/hibernate/query/criteria/spi/HibernateCriteriaBuilderDelegate.java

@@ -3669,6 +3669,18 @@ public class HibernateCriteriaBuilderDelegate implements HibernateCriteriaBuilde
 		return criteriaBuilder.xmlconcat( elements );
 	}
 
+	@Override
+	@Incubating
+	public JpaExpression<String> xmlpi(String elementName) {
+		return criteriaBuilder.xmlpi( elementName );
+	}
+
+	@Override
+	@Incubating
+	public JpaExpression<String> xmlpi(String elementName, Expression<String> content) {
+		return criteriaBuilder.xmlpi( elementName, content );
+	}
+
 	@Override
 	@Incubating
 	public <T> JpaExpression<T> named(Expression<T> expression, String name) {

hibernate-core/src/main/java/org/hibernate/query/hql/internal/SemanticQueryBuilder.java

@@ -3032,6 +3032,17 @@ public class SemanticQueryBuilder<R> extends HqlParserBaseVisitor<Object> implem
 		return creationContext.getNodeBuilder().xmlforest( elementExpressions );
 	}
 
+	@Override
+	public SqmExpression<?> visitXmlpiFunction(HqlParser.XmlpiFunctionContext ctx) {
+		checkXmlFunctionsEnabled( ctx );
+		final String name = visitIdentifier( ctx.identifier() );
+		final HqlParser.ExpressionContext exprCtx = ctx.expression();
+		//noinspection unchecked
+		return exprCtx == null
+				? creationContext.getNodeBuilder().xmlpi( name )
+				: creationContext.getNodeBuilder().xmlpi( name, (Expression<String>) exprCtx.accept( this ) );
+	}
+
 	private void checkXmlFunctionsEnabled(ParserRuleContext ctx) {
 		if ( !creationOptions.isXmlFunctionsEnabled() ) {
 			throw new SemanticException(

hibernate-core/src/main/java/org/hibernate/query/sqm/NodeBuilder.java

@@ -771,6 +771,12 @@ public interface NodeBuilder extends HibernateCriteriaBuilder, BindingContext {
 	@Override
 	SqmExpression<String> xmlconcat(List<? extends Expression<?>> elements);
 
+	@Override
+	SqmExpression<String> xmlpi(String elementName);
+
+	@Override
+	SqmExpression<String> xmlpi(String elementName, Expression<String> content);
+
 	// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 	// Covariant overrides
 

hibernate-core/src/main/java/org/hibernate/query/sqm/internal/SqmCriteriaNodeBuilder.java

@@ -5746,4 +5746,22 @@ public class SqmCriteriaNodeBuilder implements NodeBuilder, Serializable {
 				queryEngine
 		);
 	}
+
+	@Override
+	public SqmExpression<String> xmlpi(String elementName) {
+		return getFunctionDescriptor( "xmlpi" ).generateSqmExpression(
+				asList( literal( elementName ) ),
+				null,
+				queryEngine
+		);
+	}
+
+	@Override
+	public SqmExpression<String> xmlpi(String elementName, Expression<String> content) {
+		return getFunctionDescriptor( "xmlpi" ).generateSqmExpression(
+				asList( literal( elementName ), (SqmTypedNode<?>) content ),
+				null,
+				queryEngine
+		);
+	}
 }

hibernate-core/src/test/java/org/hibernate/orm/test/function/xml/XmlPiTest.java

@@ -0,0 +1,45 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.function.xml;
+
+import org.hibernate.cfg.QuerySettings;
+
+import org.hibernate.testing.orm.junit.DialectFeatureChecks;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.RequiresDialectFeature;
+import org.hibernate.testing.orm.junit.ServiceRegistry;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.hibernate.testing.orm.junit.Setting;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author Christian Beikov
+ */
+@DomainModel
+@SessionFactory
+@ServiceRegistry(settings = @Setting(name = QuerySettings.XML_FUNCTIONS_ENABLED, value = "true"))
+@RequiresDialectFeature( feature = DialectFeatureChecks.SupportsXmlpi.class)
+public class XmlPiTest {
+
+	@Test
+	public void testSimple(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			//tag::hql-xmlpi-example[]
+			em.createQuery( "select xmlpi(name php)" ).getResultList();
+			//end::hql-xmlpi-example[]
+		} );
+	}
+
+	@Test
+	public void testContent(SessionFactoryScope scope) {
+		scope.inSession( em -> {
+			//tag::hql-xmlpi-content-example[]
+			em.createQuery("select xmlpi(name `php`, 'echo \"test\"')" ).getResultList();
+			//end::hql-xmlpi-content-example[]
+		} );
+	}
+
+}

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

@@ -187,6 +187,20 @@ public class XmlFunctionTests {
 		);
 	}
 
+	@Test
+	@RequiresDialectFeature(feature = DialectFeatureChecks.SupportsXmlpi.class)
+	public void testXmlpi(SessionFactoryScope scope) {
+		scope.inTransaction(
+				session -> {
+					Tuple tuple = session.createQuery(
+							"select xmlpi(name test, 'abc')",
+							Tuple.class
+					).getSingleResult();
+					assertEquals( "<?test abc?>", tuple.get( 0, String.class ).trim() );
+				}
+		);
+	}
+
 	private void assertXmlEquals(String expected, String actual) {
 		final Document expectedDoc = parseXml( xmlNormalize( expected ) );
 		final Document actualDoc = parseXml( xmlNormalize( actual ) );

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

@@ -862,6 +862,12 @@ abstract public class DialectFeatureChecks {
 		}
 	}
 
+	public static class SupportsXmlpi implements DialectFeatureCheck {
+		public boolean apply(Dialect dialect) {
+			return definesFunction( dialect, "xmlpi" );
+		}
+	}
+
 	public static class IsJtds implements DialectFeatureCheck {
 		public boolean apply(Dialect dialect) {
 			return dialect instanceof SybaseDialect && ( (SybaseDialect) dialect ).getDriverKind() == SybaseDriverKind.JTDS;