Fix select without from in old versions of MySQL and MariaDB

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

@@ -221,6 +221,16 @@ public class MariaDBLegacySqlAstTranslator<T extends JdbcOperation> extends Abst
 		return true;
 	}
 
+	@Override
+	protected String getFromDual() {
+		return " from dual";
+	}
+
+	@Override
+	protected String getFromDualForSelectOnly() {
+		return getDialect().getVersion().isBefore( 10, 4 ) ? getFromDual() : "";
+	}
+
 	@Override
 	public MariaDBLegacyDialect getDialect() {
 		return this.dialect;

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

@@ -238,6 +238,11 @@ public class MySQLLegacySqlAstTranslator<T extends JdbcOperation> extends Abstra
 		return " from dual";
 	}
 
+	@Override
+	protected String getFromDualForSelectOnly() {
+		return getDialect().getVersion().isBefore( 5, 7 ) ? getFromDual() : "";
+	}
+
 	@Override
 	public MySQLDialect getDialect() {
 		return (MySQLDialect) super.getDialect();

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

@@ -215,6 +215,16 @@ public class MariaDBSqlAstTranslator<T extends JdbcOperation> extends AbstractSq
 		return true;
 	}
 
+	@Override
+	protected String getFromDual() {
+		return " from dual";
+	}
+
+	@Override
+	protected String getFromDualForSelectOnly() {
+		return getDialect().getVersion().isBefore( 10, 4 ) ? getFromDual() : "";
+	}
+
 	@Override
 	public MariaDBDialect getDialect() {
 		return this.dialect;

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

@@ -274,6 +274,11 @@ public class MySQLSqlAstTranslator<T extends JdbcOperation> extends AbstractSqlA
 		return " from dual";
 	}
 
+	@Override
+	protected String getFromDualForSelectOnly() {
+		return getDialect().getVersion().isBefore( 5, 7 ) ? getFromDual() : "";
+	}
+
 	@Override
 	public MySQLDialect getDialect() {
 		return (MySQLDialect) super.getDialect();