diff --git a/sqlx-core/src/arguments.rs b/sqlx-core/src/arguments.rs
index b224010334..6f830e8e57 100644
--- a/sqlx-core/src/arguments.rs
+++ b/sqlx-core/src/arguments.rs
@@ -28,7 +28,7 @@ pub trait Arguments<'q>: Send + Sized + Default {
         writer.write_str("?")
     }
 
-    fn merge(&mut self, other: Self);
+    fn merge(mut self, other: Self);
 }
 
 pub trait IntoArguments<'q, DB: Database>: Sized + Send {
diff --git a/sqlx-postgres/src/arguments.rs b/sqlx-postgres/src/arguments.rs
index 358400792b..ce56ce41e1 100644
--- a/sqlx-postgres/src/arguments.rs
+++ b/sqlx-postgres/src/arguments.rs
@@ -148,6 +148,9 @@ impl<'q> Arguments<'q> for PgArguments {
     fn merge(&mut self, other: Self) {
         self.types.extend(other.types);
         self.buffer.extend_from_slice(&other.buffer);
+        self.buffer.count += other.buffer.count;
+        self.buffer.patches.extend(other.buffer.patches);
+        self.buffer.type_holes.extend(other.buffer.type_holes);
     }
 
     #[inline(always)]