Fix regression in HQL parsing when primary alias is missing.

Original pull request: #3793
Closes #3792

Author: christophstrobl

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/HqlCountQueryTransformer.java

@@ -100,8 +100,13 @@ public QueryRendererBuilder visitFromQuery(HqlParser.FromQueryContext ctx) {
 
 		if (ctx.fromClause() != null) {
 			builder.appendExpression(visit(ctx.fromClause()));
+			if(primaryFromAlias == null) {
+				builder.append(TOKEN_AS);
+				builder.append(TOKEN_DOUBLE_UNDERSCORE);
+			}
 		}
 
+
 		if (ctx.whereClause() != null) {
 			builder.appendExpression(visit(ctx.whereClause()));
 		}

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/HqlQueryTransformerTests.java

@@ -919,11 +919,11 @@ void queryParserPicksCorrectAliasAmidstMultipleAlises() {
 		assertThat(alias("select u from User as u left join  u.roles as r")).isEqualTo("u");
 	}
 
-	@Test // GH-2032
+	@Test // GH-2032, GH-3792
 	void countQueryShouldWorkEvenWithoutExplicitAlias() {
 
 		assertCountQuery("FROM BookError WHERE portal = :portal",
-				"select count(__) FROM BookError WHERE portal = :portal");
+				"select count(__) FROM BookError AS __ WHERE portal = :portal");
 
 		assertCountQuery("FROM BookError b WHERE portal = :portal",
 				"select count(b) FROM BookError b WHERE portal = :portal");