Distinct in the QueryBuilder

lib/Doctrine/DBAL/Query/QueryBuilder.php

@@ -125,6 +125,13 @@ class QueryBuilder
      */
     private $boundCounter = 0;
 
+    /**
+     * Whether or not to include a distinct flag in the SELECT clause
+     *
+     * @var bool
+     */
+    private $isDistinct = false;
+
     /**
      * Initializes a new <tt>QueryBuilder</tt>.
      *
@@ -396,6 +403,31 @@ public function getMaxResults()
         return $this->maxResults;
     }
 
+    /**
+     * Sets the flag to only retrieve distinct results
+     *
+     * @param bool $isDistinct Set true to add the distinct flag, set to false to remove it
+     *
+     * @return $this This QueryBuilder instance.
+     */
+    public function distinct($isDistinct = true)
+    {
+        $this->state      = self::STATE_DIRTY;
+        $this->isDistinct = $isDistinct;
+
+        return $this;
+    }
+
+    /**
+     * Returns whether or not the query object is set to return only distinct results
+     *
+     * @return bool
+     */
+    public function isDistinct()
+    {
+        return $this->isDistinct;
+    }
+
     /**
      * Either appends to or replaces a single, generic query part.
      *
@@ -1099,7 +1131,7 @@ public function resetQueryPart($queryPartName)
      */
     private function getSQLForSelect()
     {
-        $query = 'SELECT ' . implode(', ', $this->sqlParts['select']);
+        $query = 'SELECT' . ($this->isDistinct ? ' DISTINCT ' : ' ') . implode(', ', $this->sqlParts['select']);
 
         $query .= ($this->sqlParts['from'] ? ' FROM ' . implode(', ', $this->getFromClauses()) : '')
             . ($this->sqlParts['where'] !== null ? ' WHERE ' . ((string) $this->sqlParts['where']) : '')

tests/Doctrine/Tests/DBAL/Query/QueryBuilderTest.php

@@ -62,6 +62,17 @@ public function testSelectWithSimpleWhere()
         self::assertEquals('SELECT u.id FROM users u WHERE u.nickname = ?', (string) $qb);
     }
 
+    public function testSelectWithDistinct()
+    {
+        $qb = new QueryBuilder($this->conn);
+
+        $qb->select('u.id')
+           ->from('users', 'u')
+           ->distinct();
+
+        self::assertEquals('SELECT DISTINCT u.id FROM users u', (string) $qb);
+    }
+
     public function testSelectWithLeftJoin()
     {
         $qb   = new QueryBuilder($this->conn);
@@ -576,6 +587,25 @@ public function testSetFirstResult()
         self::assertEquals(10, $qb->getFirstResult());
     }
 
+    public function testSetDistinct()
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->distinct();
+
+        self::assertEquals(QueryBuilder::STATE_DIRTY, $qb->getState());
+        self::assertTrue($qb->isDistinct());
+    }
+
+    public function testSetDistinctFalse()
+    {
+        $qb = new QueryBuilder($this->conn);
+        $qb->distinct(true);
+        $qb->distinct(false);
+
+        self::assertEquals(QueryBuilder::STATE_DIRTY, $qb->getState());
+        self::assertFalse($qb->isDistinct());
+    }
+
     public function testResetQueryPart()
     {
         $qb = new QueryBuilder($this->conn);