Add a basic upsert method

README.md

@@ -61,6 +61,7 @@ composer require stellarwp/db
 - [CRUD](#crud)
   - [Insert](#insert)
   - [Update](#update)
+  - [Upsert](#upsert)
   - [Delete](#delete)
   - [Get](#get)
 
@@ -847,6 +848,28 @@ DB::table('posts')
     ]);
 ```
 
+### Upsert
+
+The `QueryBuilder::upsert` method may be used to update an existing record or create a new record if it doesn't exist.
+
+```php
+// Would result in a new row - Oakland to San Diego for 100.
+DB::table('table_name')
+    ->upsert(
+        ['departure' => 'Oakland', 'destination' => 'San Diego', 'price' => '100'] ,
+        ['departure','destination']
+    );
+
+
+// Would update the row that was just inserted - Oakland to San Diego for 99.
+DB::table('table_name')
+    ->upsert(
+        ['departure' => 'Oakland', 'destination' => 'San Diego', 'price' => '99'] ,
+        ['departure','destination']
+    );
+
+```
+
 ### Delete
 
 The `QueryBuilder::delete` method may be used to delete records from the table.

src/DB/QueryBuilder/Concerns/CRUD.php

@@ -48,6 +48,28 @@ public function update( $data, $format = null ) {
 		);
 	}
 
+	/**
+	 * @param $data
+	 * @param $match
+	 * @param $format
+	 *
+	 * @return false|int
+	 */
+	public function upsert( $data, $match = [], $format = null ) {
+		// Build the where clause(s).
+		foreach( $match as $column ) {
+			$this->where( $column, $data[$column] );
+		}
+
+		// If the row exists, update it.
+		if ( $this->get() ) {
+			return $this->update( $data, $format );
+		}
+
+		// Otherwise, insert it.
+		return $this->insert( $data, $format );
+	}
+
 	/**
 	 * @since 1.0.0
 	 *

tests/wpunit/QueryBuilder/CRUDTest.php

@@ -129,4 +129,89 @@ public function testDeleteShouldDeleteRowInDatabase()
         $this->assertNull($post);
     }
 
+	/**
+	 * Tests if upsert() adds a row to the database.
+	 *
+	 * @return void
+	 */
+	public function testUpsertShouldAddRowToDatabase()
+	{
+		$data = [
+			'post_title' => 'Query Builder CRUD test',
+			'post_type' => 'crud_test',
+			'post_content' => 'Hello World!',
+		];
+
+		DB::table('posts')->upsert($data);
+
+		$id = DB::last_insert_id();
+
+		$post = DB::table('posts')
+			->select('post_title', 'post_type', 'post_content')
+			->where('ID', $id)
+			->get();
+
+		$this->assertEquals($data['post_title'], $post->post_title);
+		$this->assertEquals($data['post_type'], $post->post_type);
+		$this->assertEquals($data['post_content'], $post->post_content);
+	}
+
+	/**
+	 * Tests if upsert() updates a row in the database.
+	 *
+	 * @return void
+	 */
+	public function testUpsertShouldUpdateRowInDatabase()
+	{
+		$data = [
+			'post_title' => 'Query Builder CRUD test - upsert update',
+			'post_type' => 'crud_test',
+			'post_content' => 'Hello World from upsert!',
+		];
+
+		DB::table('posts')->insert($data);
+
+		$original_id = DB::last_insert_id();
+
+		$updated_data = [
+			'post_title' => 'Query Builder CRUD test - upsert update',
+			'post_type' => 'crud_test',
+			'post_content' => 'Hello World from upsert! - updated',
+		];
+
+		$match = [
+			'post_title',
+		];
+
+		DB::table('posts')->upsert( $updated_data, $match );
+
+		$post = DB::table('posts')
+			->select('post_title', 'post_type', 'post_content')
+			->where('ID', $original_id)
+			->get();
+
+		$this->assertEquals($updated_data['post_content'], $post->post_content);
+
+		// Test multiple match columns
+		$further_updated_data = [
+			'post_title' => 'Query Builder CRUD test - upsert update',
+			'post_type' => 'crud_test',
+			'post_content' => 'Hello World from upsert! - updated even more!',
+		];
+
+		$match = [
+			'post_title',
+			'post_type',
+		];
+
+		DB::table('posts')->upsert( $further_updated_data, $match );
+
+		$post = DB::table('posts')
+			->select('post_title', 'post_type', 'post_content')
+			->where('ID', $original_id)
+			->get();
+
+		$this->assertEquals($further_updated_data['post_content'], $post->post_content);
+	}
+
 }