Merge pull request #2160 from MGatner/select-count

Add BaseBuilder SelectCount

Author: lonnieezell

system/Database/BaseBuilder.php

@@ -384,7 +384,24 @@ public function selectSum(string $select = '', string $alias = '')
 	//--------------------------------------------------------------------
 
 	/**
-	 * SELECT [MAX|MIN|AVG|SUM]()
+	 * Select Count
+	 *
+	 * Generates a SELECT COUNT(field) portion of a query
+	 *
+	 * @param string $select The field
+	 * @param string $alias  An alias
+	 *
+	 * @return BaseBuilder
+	 */
+	public function selectCount(string $select = '', string $alias = '')
+	{
+		return $this->maxMinAvgSum($select, $alias, 'COUNT');
+	}
+
+	//--------------------------------------------------------------------
+
+	/**
+	 * SELECT [MAX|MIN|AVG|SUM|COUNT]()
 	 *
 	 * @used-by selectMax()
 	 * @used-by selectMin()
@@ -413,7 +430,7 @@ protected function maxMinAvgSum(string $select = '', string $alias = '', string
 
 		$type = strtoupper($type);
 
-		if (! in_array($type, ['MAX', 'MIN', 'AVG', 'SUM']))
+		if (! in_array($type, ['MAX', 'MIN', 'AVG', 'SUM', 'COUNT']))
 		{
 			throw new DatabaseException('Invalid function type: ' . $type);
 		}

tests/system/Database/Builder/SelectTest.php

@@ -199,6 +199,32 @@ public function testSelectSumWithAlias()
 
 	//--------------------------------------------------------------------
 
+	public function testSelectCountWithNoAlias()
+	{
+		$builder = new BaseBuilder('invoices', $this->db);
+
+		$builder->selectCount('payments');
+
+		$expected = 'SELECT COUNT("payments") AS "payments" FROM "invoices"';
+
+		$this->assertEquals($expected, str_replace("\n", ' ', $builder->getCompiledSelect()));
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testSelectCountWithAlias()
+	{
+		$builder = new BaseBuilder('invoices', $this->db);
+
+		$builder->selectCount('payments', 'myAlias');
+
+		$expected = 'SELECT COUNT("payments") AS "myAlias" FROM "invoices"';
+
+		$this->assertEquals($expected, str_replace("\n", ' ', $builder->getCompiledSelect()));
+	}
+
+	//--------------------------------------------------------------------
+
 	public function testSelectMinThrowsExceptionOnEmptyValue()
 	{
 		$builder = new BaseBuilder('invoices', $this->db);

tests/system/Database/Live/GroupTest.php

@@ -123,4 +123,15 @@ public function testOrNotGroups()
 
 	//--------------------------------------------------------------------
 
+	public function testGroupByCount()
+	{
+		$result = $this->db->table('user')
+				->selectCount('id', 'count')
+				->groupBy('country')
+				->orderBy('country', 'desc')
+				->get()
+				->getResult();
+
+		$this->assertEquals(2, $result[0]->count);
+	}
 }

tests/system/Database/Live/SelectTest.php

@@ -91,7 +91,7 @@ public function testSelectAvg()
 
 	//--------------------------------------------------------------------
 
-	public function testSelectAvgWitAlias()
+	public function testSelectAvgWithAlias()
 	{
 		$result = $this->db->table('job')->selectAvg('id', 'xam')->get()->getRow();
 
@@ -109,7 +109,7 @@ public function testSelectSum()
 
 	//--------------------------------------------------------------------
 
-	public function testSelectSumWitAlias()
+	public function testSelectSumWithAlias()
 	{
 		$result = $this->db->table('job')->selectSum('id', 'xam')->get()->getRow();
 
@@ -118,6 +118,24 @@ public function testSelectSumWitAlias()
 
 	//--------------------------------------------------------------------
 
+	public function testSelectCount()
+	{
+		$result = $this->db->table('job')->selectCount('id')->get()->getRow();
+
+		$this->assertEquals(4, $result->id);
+	}
+
+	//--------------------------------------------------------------------
+
+	public function testSelectCountWithAlias()
+	{
+		$result = $this->db->table('job')->selectCount('id', 'xam')->get()->getRow();
+
+		$this->assertEquals(4, $result->xam);
+	}
+
+	//--------------------------------------------------------------------
+
 	public function testSelectDistinctWorkTogether()
 	{
 		$users = $this->db->table('user')->select('country')->distinct()->get()->getResult();

user_guide_src/source/database/query_builder.rst

@@ -172,6 +172,20 @@ Writes a "SELECT SUM(field)" portion for your query. As with
 selectMax(), You can optionally include a second parameter to rename
 the resulting field.
 
+::
+
+	$builder->selectSum('age');
+	$query = $builder->get(); // Produces: SELECT SUM(age) as age FROM mytable
+
+**$builder->selectCount()**
+
+Writes a "SELECT COUNT(field)" portion for your query. As with
+selectMax(), You can optionally include a second parameter to rename
+the resulting field.
+
+.. note:: This method is particularly helpful when used with ``groupBy()``. For
+counting results generally see ``countAll()`` or ``countAllResults()``.
+
 ::
 
 	$builder->selectSum('age');