Updated query to support old mysql version (#22606)

* Updated query to support old mysql version

* Added tests

* Using foundation for tests

* Removed unused override params

* Removed unused override params

server/boards/services/store/sqlstore/boards_migrator.go

@@ -231,6 +231,9 @@ func (bm *BoardsMigrator) MigrateToStep(step int) error {
 func (bm *BoardsMigrator) Interceptors() map[int]foundation.Interceptor {
 	return map[int]foundation.Interceptor{
 		18: bm.store.RunDeletedMembershipBoardsMigration,
+		35: func() error {
+			return bm.store.RunDeDuplicateCategoryBoardsMigration(35)
+		},
 	}
 }
 

server/boards/services/store/sqlstore/data_migrations.go

@@ -863,10 +863,8 @@ func (s *SQLStore) doesDuplicateCategoryBoardsExist() (bool, error) {
 }
 
 func (s *SQLStore) runMySQLDeDuplicateCategoryBoardsMigration() error {
-	query := "WITH duplicates AS (SELECT id, ROW_NUMBER() OVER(PARTITION BY user_id, board_id) AS rownum " +
-		"FROM " + s.tablePrefix + "category_boards) " +
-		"DELETE " + s.tablePrefix + "category_boards FROM " + s.tablePrefix + "category_boards " +
-		"JOIN duplicates USING(id) WHERE duplicates.rownum > 1;"
+	query := "DELETE FROM " + s.tablePrefix + "category_boards WHERE id NOT IN " +
+		"(SELECT * FROM ( SELECT min(id) FROM " + s.tablePrefix + "category_boards GROUP BY user_id, board_id ) as data)"
 	if _, err := s.db.Exec(query); err != nil {
 		s.logger.Error("Failed to de-duplicate data in category_boards table", mlog.Err(err))
 	}

server/boards/services/store/sqlstore/data_migrations_test.go

@@ -7,6 +7,9 @@ import (
 	"testing"
 	"time"
 
+	"github.com/mattermost/mattermost-server/v6/server/boards/services/store/sqlstore/migrationstests"
+	"github.com/mgdelacroix/foundation"
+
 	"github.com/mattermost/mattermost-server/v6/server/boards/model"
 
 	"github.com/stretchr/testify/assert"
@@ -263,3 +266,23 @@ func TestCheckForMismatchedCollation(t *testing.T) {
 		}
 	})
 }
+
+func TestRunDeDuplicateCategoryBoardsMigration(t *testing.T) {
+	RunStoreTestsWithFoundation(t, func(t *testing.T, f *foundation.Foundation) {
+		th, tearDown := migrationstests.SetupTestHelper(t, f)
+		defer tearDown()
+
+		th.F().MigrateToStepSkippingLastInterceptor(35).
+			ExecFile("./fixtures/testDeDuplicateCategoryBoardsMigration.sql")
+
+		th.F().RunInterceptor(35)
+
+		// verifying count of rows
+		var count int
+		countQuery := "SELECT COUNT(*) FROM focalboard_category_boards"
+		row := th.F().DB().QueryRow(countQuery)
+		err := row.Scan(&count)
+		assert.NoError(t, err)
+		assert.Equal(t, 4, count)
+	})
+}

server/boards/services/store/sqlstore/fixtures/testDeDuplicateCategoryBoardsMigration.sql

@@ -0,0 +1,9 @@
+INSERT INTO focalboard_category_boards(id, user_id, category_id, board_id, create_at, update_at, sort_order)
+VALUES
+    ('id_1', 'user_id_1', 'category_id_1', 'board_id_1', 0, 0, 0),
+    ('id_2', 'user_id_1', 'category_id_2', 'board_id_1', 0, 0, 0),
+    ('id_3', 'user_id_1', 'category_id_3', 'board_id_1', 0, 0, 0),
+    ('id_4', 'user_id_2', 'category_id_4', 'board_id_2', 0, 0, 0),
+    ('id_5', 'user_id_2', 'category_id_5', 'board_id_2', 0, 0, 0),
+    ('id_6', 'user_id_3', 'category_id_6', 'board_id_3', 0, 0, 0),
+    ('id_7', 'user_id_4', 'category_id_6', 'board_id_4', 0, 0, 0);

server/boards/services/store/sqlstore/migrationstests/helpers.go

@@ -22,6 +22,10 @@ func (th *TestHelper) IsMySQL() bool {
 	return th.f.DB().DriverName() == "mysql"
 }
 
+func (th *TestHelper) F() *foundation.Foundation {
+	return th.f
+}
+
 func SetupTestHelper(t *testing.T, f *foundation.Foundation) (*TestHelper, func()) {
 	th := &TestHelper{t, f}
 

server/boards/services/store/sqlstore/testlib.go

@@ -50,6 +50,7 @@ func NewStoreType(name string, driver string, skipMigrations bool) *storeType {
 		DB:               sqlDB,
 		IsPlugin:         false, // ToDo: to be removed
 	}
+
 	store, err := New(storeParams)
 	if err != nil {
 		panic(fmt.Sprintf("cannot create store: %s", err))