fix: split merge into (#550)

Author: psteinroe

crates/pgt_statement_splitter/src/lib.rs

@@ -537,6 +537,32 @@ values ('insert', new.id, now());",
         ]);
     }
 
+    #[test]
+    fn merge_into() {
+        Tester::from(
+            "MERGE INTO course_permissions AS cp
+USING (SELECT 1 AS user_id, 2 AS course_id, 'Owner'::enum_course_role AS course_role) AS data
+ON (cp.course_id = data.course_id AND cp.user_id = data.user_id)
+WHEN MATCHED THEN UPDATE SET course_role = data.course_role
+WHEN NOT MATCHED THEN
+INSERT
+  (user_id, course_id, course_role)
+VALUES
+  (data.user_id, data.course_id, data.course_role);",
+        )
+        .expect_statements(vec![
+            "MERGE INTO course_permissions AS cp
+USING (SELECT 1 AS user_id, 2 AS course_id, 'Owner'::enum_course_role AS course_role) AS data
+ON (cp.course_id = data.course_id AND cp.user_id = data.user_id)
+WHEN MATCHED THEN UPDATE SET course_role = data.course_role
+WHEN NOT MATCHED THEN
+INSERT
+  (user_id, course_id, course_role)
+VALUES
+  (data.user_id, data.course_id, data.course_role);",
+        ]);
+    }
+
     #[test]
     fn commas_and_newlines() {
         Tester::from(

crates/pgt_statement_splitter/src/splitter/common.rs

@@ -263,6 +263,8 @@ pub(crate) fn unknown(p: &mut Splitter, exclude: &[SyntaxKind]) {
                         SyntaxKind::DO_KW,
                         // FOR NO KEY UPDATE
                         SyntaxKind::KEY_KW,
+                        // WHEN MATCHED THEN
+                        SyntaxKind::THEN_KW,
                     ]
                     .iter()
                     .all(|x| Some(x) != prev.as_ref())