Fix for #158 - Add support for using setDistinct (by excluding id property from generated sql)

src/main/java/com/avaje/ebeaninternal/api/SpiQuery.java

@@ -532,12 +532,24 @@ public interface SpiQuery<T> extends Query<T> {
      * Return the index of the first row to return in the query.
      */
     public int getFirstRow();
+    
+    /**
+     * Internally set by Ebean when this query must use the DISTINCT keyword.
+     * <p>
+     * This does not exclude/remove the use of the id property.
+     */
+    public Query<T> setSqlDistinct(boolean sqlDistinct);
 
     /**
-     * return true if this query uses DISTINCT.
+     * Return true if this query has been specified by a user or internally by Ebean to use DISTINCT.
+     */
+    public boolean isDistinctQuery();
+
+    /**
+     * Return true if this query has been specified by a user to use DISTINCT.
      */
     public boolean isDistinct();
-
+    
     /**
      * Set default select clauses where none have been explicitly defined.
      */

src/main/java/com/avaje/ebeaninternal/server/core/DefaultServer.java

@@ -1112,7 +1112,7 @@ public final class DefaultServer implements SpiEbeanServer {
     // predicates on *ToMany properties
     if (query.initManyWhereJoins()) {
       // we need a sql distinct now
-      query.setDistinct(true);
+      query.setSqlDistinct(true);
     }
 
     boolean allowOneManyFetch = true;

src/main/java/com/avaje/ebeaninternal/server/query/CQueryBuilder.java

@@ -144,7 +144,7 @@ public class CQueryBuilder implements Constants {
     String sqlSelect = "select count(*)";
     if (hasMany) {
       // need to count distinct id's ...
-      query.setDistinct(true);
+      query.setSqlDistinct(true);
       sqlSelect = null;
     }
 
@@ -320,13 +320,13 @@ public class CQueryBuilder implements Constants {
 
       if (!useSqlLimiter) {
         sb.append("select ");
-        if (query.isDistinct()) {
+        if (query.isDistinctQuery()) {
           sb.append("distinct ");
         }
       }
 
       sb.append(select.getSelectSql());
-      if (query.isDistinct() && dbOrderBy != null) {
+      if (query.isDistinctQuery() && dbOrderBy != null) {
         // add the orderby columns to the select clause (due to distinct)
         sb.append(", ").append(convertDbOrderByForSelect(dbOrderBy));
       }

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeBuilder.java

@@ -258,7 +258,8 @@ public class SqlTreeBuilder {
 
       // Optional many property for lazy loading query
       BeanPropertyAssocMany<?> lazyLoadMany = (query == null) ? null : query.getLazyLoadForParentsProperty();
-      return new SqlTreeNodeRoot(desc, props, myList, !subQuery, includeJoin, lazyLoadMany);
+      boolean withId = !subQuery && (query == null || !query.isDistinct());
+      return new SqlTreeNodeRoot(desc, props, myList, withId, includeJoin, lazyLoadMany);
 
     } else if (prop instanceof BeanPropertyAssocMany<?>) {
       return new SqlTreeNodeManyRoot(prefix, (BeanPropertyAssocMany<?>) prop, props, myList);
@@ -312,7 +313,7 @@ public class SqlTreeBuilder {
           // as we are now going to join to the many then we need
           // to add the distinct to the sql query to stop duplicate
           // rows...
-          query.setDistinct(true);
+          query.setSqlDistinct(true);
         }
       }
     }

src/main/java/com/avaje/ebeaninternal/server/query/SqlTreeNodeBean.java

@@ -194,7 +194,7 @@ public class SqlTreeNodeBean implements SqlTreeNode {
 
     Mode queryMode = ctx.getQueryMode();
 
-    PersistenceContext persistenceContext = ctx.getPersistenceContext();
+    PersistenceContext persistenceContext = !readId ? null : ctx.getPersistenceContext();
 
     Object id = null;
     if (!readId) {
@@ -274,8 +274,9 @@ public class SqlTreeNodeBean implements SqlTreeNode {
     } else if (localBean != null) {
 
       ctx.setCurrentPrefix(prefix, pathMap);
-      createListProxies(localDesc, ctx, localBean);
-
+      if (readId) {
+        createListProxies(localDesc, ctx, localBean);
+      }
       localDesc.postLoad(localBean, null);
 
       if (localBean instanceof EntityBean) {
@@ -290,7 +291,10 @@ public class SqlTreeNodeBean implements SqlTreeNode {
         }
 
         if (partialObject) {
-          ctx.register(null, ebi);
+          if (readId) {
+            // register for lazy loading 
+            ctx.register(null, ebi);
+          }
         } else {
           ebi.setFullyLoadedBean(true);
         }

src/main/java/com/avaje/ebeaninternal/server/querydefn/DefaultOrmQuery.java

@@ -128,11 +128,16 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 	private String lazyLoadProperty;
 	
   private String lazyLoadManyPath;
-	
+
+  /**
+   * Set to true by a user wanting a DISTINCT query (id property must be excluded).
+   */
+  private boolean distinct;
+
 	/**
-	 * Set to true if you want a DISTINCT query.
+	 * Set to true internally by Ebean when it needs the DISTINCT keyword added to the query (id property still expected).
 	 */
-	private boolean distinct;
+	private boolean sqlDistinct;
 	
 	/**
 	 * Set to true if this is a future fetch using background threads.
@@ -431,7 +436,8 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 		copy.query = query;
 		copy.additionalWhere = additionalWhere;
 		copy.additionalHaving = additionalHaving;
-		copy.distinct = distinct;
+    copy.distinct = distinct;
+		copy.sqlDistinct = sqlDistinct;
 		copy.timeout = timeout;
 		copy.mapKey = mapKey;
 		copy.id = id;
@@ -658,7 +664,7 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 	  }
 
 	  builder.add((type == null ? 0 : type.ordinal()+1));
-	  builder.add(autoFetchTuned).add(distinct).add(query);
+	  builder.add(autoFetchTuned).add(distinct).add(sqlDistinct).add(query);
     builder.add(firstRow).add(maxRows).add(orderBy).add(forUpdate);
     builder.add(rawWhereClause).add(additionalWhere).add(additionalHaving);
     builder.add(mapKey);
@@ -1022,19 +1028,33 @@ public class DefaultOrmQuery<T> implements SpiQuery<T> {
 		return this;
 	}
 
+  /**
+   * return true if user specified to use SQL DISTINCT (effectively excludes id property).
+   */
+  public boolean isDistinct() {
+    return distinct;
+  }
+
+  /**
+   * Internally set to use SQL DISTINCT on the query but still have id property included.
+   */
+  public DefaultOrmQuery<T> setDistinct(boolean distinct) {
+    this.distinct = distinct;
+    return this;
+  }
 
 	/**
-	 * return true if this query uses DISTINCT.
+	 * Return true if this query uses SQL DISTINCT either explicitly by the user or internally defined by ebean.
 	 */
-	public boolean isDistinct() {
-		return distinct;
+	public boolean isDistinctQuery() {
+		return distinct || sqlDistinct;
 	}
 
 	/**
-	 * Set whether this query uses DISTINCT.
+	 * Internally set to use SQL DISTINCT on the query but still have id property included.
 	 */
-	public DefaultOrmQuery<T> setDistinct(boolean isDistinct) {
-		this.distinct = isDistinct;
+	public DefaultOrmQuery<T> setSqlDistinct(boolean sqlDistinct) {
+		this.sqlDistinct = sqlDistinct;
 		return this;
 	}
 

src/main/java/com/avaje/ebeaninternal/server/querydefn/OrmQueryLimitRequest.java

@@ -38,7 +38,7 @@ public class OrmQueryLimitRequest implements SqlLimitRequest {
 	}
 
 	public boolean isDistinct() {
-		return ormQuery.isDistinct();
+		return ormQuery.isDistinctQuery();
 	}
 
   public SpiQuery<?> getOrmQuery() {