diff --git a/src/Fluent/Connection.php b/src/Fluent/Connection.php
index 7c6b30e..d9f5176 100644
--- a/src/Fluent/Connection.php
+++ b/src/Fluent/Connection.php
@@ -403,7 +403,7 @@ public function merge(?string $into = NULL, ?string $alias = NULL): Query
 
 
 	/**
-	 * @param array<string, mixed>|string|Query|Db\Sql $dataSource values, table or query
+	 * @param string|Query|Db\Sql $dataSource values, table or query
 	 * @param string|Complex|Db\Sql|NULL $onCondition
 	 * @return QueryExecute
 	 * @throws Exceptions\QueryException
diff --git a/src/Fluent/Query.php b/src/Fluent/Query.php
index 04f722b..32cc79e 100644
--- a/src/Fluent/Query.php
+++ b/src/Fluent/Query.php
@@ -56,6 +56,8 @@ class Query implements Sql
 	public const MERGE_USING_DATA_SOURCE = 'using-data-source';
 	public const MERGE_USING_ALIAS = 'using-alias';
 	public const MERGE_WHEN = 'when';
+	public const MERGE_WHEN_MATCHED = 'when-matched';
+	public const MERGE_WHEN_NOT_MATCHED = 'when-not-matched';
 
 	public const WITH_QUERIES = 'queries';
 	public const WITH_QUERIES_SUFFIX = 'queries-suffix';
@@ -672,7 +674,7 @@ public function merge(?string $into = NULL, ?string $alias = NULL): self
 
 
 	/**
-	 * @param array<string, mixed>|string|self|Db\Sql $dataSource values, table or query
+	 * @param string|self|Db\Sql $dataSource values, table or query
 	 * @param string|Complex|Db\Sql|NULL $onCondition
 	 * @return static
 	 * @throws Exceptions\QueryException
@@ -682,6 +684,7 @@ public function using($dataSource, ?string $alias = NULL, $onCondition = NULL):
 		$this->resetQuery();
 		$this->queryType = self::QUERY_MERGE;
 		$this->params[self::MERGE_USING_DATA_SOURCE] = $dataSource;
+		$this->params[self::MERGE_USING_ALIAS] = $alias;
 		return $this;
 	}
 
@@ -693,6 +696,9 @@ public function using($dataSource, ?string $alias = NULL, $onCondition = NULL):
 	 */
 	public function whenMatched(string $then, $onCondition = NULL): self
 	{
+		$this->resetQuery();
+		$this->params[self::MERGE_WHEN][] = [self::MERGE_WHEN_MATCHED, $then, $onCondition];
+		return $this;
 	}
 
 
@@ -703,6 +709,9 @@ public function whenMatched(string $then, $onCondition = NULL): self
 	 */
 	public function whenNotMatched(string $then, $onCondition = NULL): self
 	{
+		$this->resetQuery();
+		$this->params[self::MERGE_WHEN][] = [self::MERGE_WHEN_NOT_MATCHED, $then, $onCondition];
+		return $this;
 	}
 
 
diff --git a/src/Fluent/Sql.php b/src/Fluent/Sql.php
index 2167d84..e9a4e1d 100644
--- a/src/Fluent/Sql.php
+++ b/src/Fluent/Sql.php
@@ -211,7 +211,7 @@ function merge(?string $into = NULL, ?string $alias = NULL): Query;
 
 
 	/**
-	 * @param array<string, mixed>|string|Query|Db\Sql $dataSource values, table or query
+	 * @param string|Query|Db\Sql $dataSource values, table or query
 	 * @param string|Complex|Db\Sql|NULL $onCondition
 	 */
 	function using($dataSource, ?string $alias = NULL, $onCondition = NULL): Query;