#1619 - Support aggregation formula on fetch clause e.g. query.fetch("machineUsage", "sum(totalKms)")

src/main/java/io/ebeaninternal/server/deploy/BeanDescriptor.java

@@ -2586,9 +2586,9 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType {
   /**
    * Return a 'dynamic property' used to read a formula.
    */
-  private STreeProperty findSqlTreeFormula(String formulaExpression) {
-
-    return dynamicProperty.computeIfAbsent(formulaExpression, (formula) -> new FormulaPropertyPath(this, formula).build());
+  private STreeProperty findSqlTreeFormula(String formula, String path) {
+    String key = formula + "-" + path;
+    return dynamicProperty.computeIfAbsent(key, (fullKey) -> new FormulaPropertyPath(this, formula, path).build());
   }
 
   /**
@@ -2597,9 +2597,9 @@ public class BeanDescriptor<T> implements BeanType<T>, STreeType {
    * The property can be a dynamic formula or a well known bean property.
    */
   @Override
-  public STreeProperty findPropertyWithDynamic(String propName) {
+  public STreeProperty findPropertyWithDynamic(String propName, String path) {
     if (propName.indexOf('(') > -1) {
-      return findSqlTreeFormula(propName);
+      return findSqlTreeFormula(propName, path);
     }
     return _findBeanProperty(propName);
   }

src/main/java/io/ebeaninternal/server/deploy/FormulaPropertyPath.java

@@ -20,15 +20,17 @@ class FormulaPropertyPath {
 
   private final String internalExpression;
 
+  private final String path;
+
   private boolean countDistinct;
 
   private String cast;
   private String alias;
 
-  FormulaPropertyPath(BeanDescriptor<?> descriptor, String formula) {
-
+  FormulaPropertyPath(BeanDescriptor<?> descriptor, String formula, String path) {
     this.descriptor = descriptor;
     this.formula = formula;
+    this.path = path;
 
     int openBracket = formula.indexOf('(');
     int closeBracket = formula.lastIndexOf(')');
@@ -94,6 +96,11 @@ class FormulaPropertyPath {
     DeployPropertyParser parser = descriptor.parser().setCatchFirst(true);
 
     String parsed = parser.parse(internalExpression);
+    if (path != null) {
+      // fetch("machineStats", "sum(hours), sum(totalKms)")
+      parsed = parsed.replace("${}", "${" + path + "}");
+    }
+
     ElPropertyDeploy firstProp = parser.getFirstProp();
 
     ScalarType<?> scalarType;

src/main/java/io/ebeaninternal/server/query/STreeType.java

@@ -120,7 +120,7 @@ public interface STreeType {
   /**
    * Find and return property allowing for dynamic formula properties.
    */
-  STreeProperty findPropertyWithDynamic(String baseName);
+  STreeProperty findPropertyWithDynamic(String baseName, String path);
 
   /**
    * Return an extra join if the property path requires it.

src/main/java/io/ebeaninternal/server/query/SqlTreeBuilder.java

@@ -273,7 +273,10 @@ public final class SqlTreeBuilder {
     OrmQueryProperties queryProps = queryDetail.getChunk(prefix, false);
     SqlTreeProperties props = getBaseSelect(desc, queryProps);
 
-    if (prefix == null && !rawSql) {
+    if (prefix != null) {
+      // check for aggregation on a fetch
+      props.checkAggregation();
+    } else if (!rawSql) {
       if (props.requireSqlDistinct(manyWhereJoins)) {
         sqlDistinct = true;
       }
@@ -417,10 +420,10 @@ public final class SqlTreeBuilder {
 
       // make sure we only included the base/embedded bean once
       if (!selectProps.containsProperty(baseName)) {
-        STreeProperty p = desc.findPropertyWithDynamic(baseName);
+        STreeProperty p = desc.findPropertyWithDynamic(baseName, null);
         if (p == null) {
           // maybe dynamic formula with schema prefix
-          p = desc.findPropertyWithDynamic(propName);
+          p = desc.findPropertyWithDynamic(propName, null);
           if (p != null) {
             selectProps.add(p);
           } else {
@@ -437,7 +440,7 @@ public final class SqlTreeBuilder {
     } else {
       // find the property including searching the
       // sub class hierarchy if required
-      STreeProperty p = desc.findPropertyWithDynamic(propName);
+      STreeProperty p = desc.findPropertyWithDynamic(propName, queryProps.getPath());
       if (p == null) {
         logger.error("property [" + propName + "] not found on " + desc + " for query - excluding it.");
         p = desc.findProperty("id");

src/main/java/io/ebeaninternal/server/query/SqlTreeNodeBean.java

@@ -378,7 +378,7 @@ class SqlTreeNodeBean implements SqlTreeNode {
 
     if (!readId || temporalVersions) {
       // a bean with no Id (never found in context)
-      if (lazyLoadParentId != null && desc.isElementType()) {
+      if (lazyLoadParentId != null) {
         ctx.setLazyLoadedChildBean(localBean, lazyLoadParentId);
       }
       return localBean;
@@ -422,6 +422,9 @@ class SqlTreeNodeBean implements SqlTreeNode {
 
     ctx.pushJoin(prefix);
     ctx.pushTableAlias(prefix);
+    if (lazyLoadParent != null) {
+      lazyLoadParent.addSelectExported(ctx, prefix);
+    }
     if (readId) {
       appendSelectId(ctx, idBinder.getBeanProperty());
     }
@@ -486,7 +489,15 @@ class SqlTreeNodeBean implements SqlTreeNode {
 
   @Override
   public boolean isAggregation() {
-    return aggregation;
+    if (aggregation) {
+      return true;
+    }
+    for (SqlTreeNode child : children) {
+      if (child.isAggregation()) {
+        return true;
+      }
+    }
+    return false;
   }
 
   /**

src/main/java/io/ebeaninternal/server/query/SqlTreeProperties.java

@@ -92,6 +92,13 @@ public class SqlTreeProperties {
     return aggregation;
   }
 
+  /**
+   * Check for aggregation (need for groug by clause).
+   */
+  public void checkAggregation() {
+    aggregationJoin();
+  }
+
   /**
    * Return the property to join for aggregation.
    */