Merge branch 'developer'

src/Query/Sql/Exists.php

@@ -0,0 +1,34 @@
+<?php namespace ClanCats\Hydrahon\Query\Sql;
+
+/**
+ * Exists query 
+ * 
+ * Allows building queries like "SELECT EXISTS(select * from showtimes) as hasShows"
+ **
+ * @package         Hydrahon
+ * @copyright       2015 Mario Döring
+ */
+
+use ClanCats\Hydrahon\BaseQuery;
+
+class Exists extends BaseQuery
+{
+	/**
+	 * The select query we want to check if 
+	 * any results exists
+	 * 
+	 * @var Select
+	 */
+    protected $select = null;
+
+    /**
+     * Sets the select query
+     * 
+     * @param Select 				$select
+     * @return void
+     */
+    public function setSelect(Select $select)
+    {
+    	$this->select = $select;
+    }
+}

src/Query/Sql/Select.php

@@ -630,4 +630,27 @@ public function avg($field)
     {
         return $this->column(new Func('avg', $field));
     }
+
+    /** 
+     * Do any results of this query exist?
+     * 
+     * @return bool
+     */
+    public function exists()
+    {
+        $existsQuery = new Exists($this);
+
+        // set the current select for the exists query
+        $existsQuery->setSelect($this);
+
+        // run the callbacks to retirve the results
+        $result = $existsQuery->executeResultFetcher();
+
+        if (isset($result[0]['exists']))
+        {
+            return (bool) $result[0]['exists'];
+        }
+
+        return false;
+    }
 }

src/Translator/Mysql.php

@@ -19,6 +19,7 @@
 use ClanCats\Hydrahon\Query\Sql\Drop;
 use ClanCats\Hydrahon\Query\Sql\Truncate;
 use ClanCats\Hydrahon\Query\Sql\Func;
+use ClanCats\Hydrahon\Query\Sql\Exists;
 
 class Mysql implements TranslatorInterface
 {
@@ -86,6 +87,10 @@ public function translate(BaseQuery $query)
         {
             $queryString = $this->translateTruncate();
         }
+        elseif ($query instanceof Exists)
+        {
+            $queryString = $this->translateExists();
+        }
         // everything else is wrong
         else
         {
@@ -683,4 +688,25 @@ protected function translateTruncate()
     {
         return 'truncate table ' . $this->escapeTable() .';';
     }
+
+    /**
+     * Translate the exists querry
+     *
+     * @return string
+     */
+    protected function translateExists()
+    {
+        $translator = new static;
+
+        // translate the subselect
+        list($subQuery, $subQueryParameters) = $translator->translate($this->attr('select'));
+
+        // merge the parameters
+        foreach($subQueryParameters as $parameter)
+        {
+            $this->addParameter($parameter);
+        }
+
+        return 'select exists(' . $subQuery .') as `exists`';
+    }
 }

tests/Translator/Mysql.php

@@ -679,4 +679,34 @@ public function testAvg()
 			return $q->table('test')->select()->avg('views');
 		});
 	}
+
+	/**
+	 * mysql grammar tests
+	 */
+	public function testExists()
+	{
+		$this->assertQueryExecution(array(array('exists' => 1)), true, 'select exists(select * from `test`) as `exists`', array(), function($q)
+		{
+			return $q->table('test')->select()->exists();
+		});
+
+		// no results
+		$this->assertQueryExecution(array(array('exists' => 0)), false, 'select exists(select * from `test`) as `exists`', array(), function($q)
+		{
+			return $q->table('test')->select()->exists();
+		});
+
+		// with some statements
+		$this->assertQueryExecution(array(array('exists' => 0)), false, 'select exists(select * from `test` where ( `a` = ? or `c` = ? )) as `exists`', array('b', 'd'), function($q)
+		{
+			return $q->table('test')
+				->select()
+				->where(function( $q )
+				{
+					$q->where('a', 'b');
+					$q->orWhere('c', 'd');
+				})
+				->exists();
+		});
+	}
 }