implements where for onConflict

add test for where for onConflict

moor/lib/src/runtime/query_builder/statements/insert.dart

@@ -197,6 +197,13 @@ class InsertStatement<T extends Table, D> {
 
         first = false;
       }
+
+      if (onConflict._where != null) {
+        ctx.writeWhitespace();
+        final where = onConflict._where!(
+            table.asDslTable, table.createAlias('excluded').asDslTable);
+        where.writeInto(ctx);
+      }
     }
 
     if (onConflict is DoUpdate<T, D>) {
@@ -301,6 +308,8 @@ abstract class UpsertClause<T extends Table, D> {}
 /// For an example, see [InsertStatement.insert].
 class DoUpdate<T extends Table, D> extends UpsertClause<T, D> {
   final Insertable<D> Function(T old, T excluded) _creator;
+  final Where Function(T old, T excluded)? _where;
+
   final bool _usesExcludedTable;
 
   /// An optional list of columns to serve as an "conflict target", which
@@ -317,8 +326,10 @@ class DoUpdate<T extends Table, D> extends UpsertClause<T, D> {
   /// been inserted, use [DoUpdate.withExcluded].
   ///
   /// For an example, see [InsertStatement.insert].
-  DoUpdate(Insertable<D> Function(T old) update, {this.target})
+  DoUpdate(Insertable<D> Function(T old) update,
+      {this.target, Expression<bool?> Function(T old)? where})
       : _creator = ((old, _) => update(old)),
+        _where = where == null ? null : ((old, _) => Where(where(old))),
         _usesExcludedTable = false;
 
   /// Creates a `DO UPDATE` clause.
@@ -330,8 +341,12 @@ class DoUpdate<T extends Table, D> extends UpsertClause<T, D> {
   /// parameter.
   ///
   /// For an example, see [InsertStatement.insert].
-  DoUpdate.withExcluded(this._creator, {this.target})
+  DoUpdate.withExcluded(this._creator,
-      : _usesExcludedTable = true;
+      {this.target, Expression<bool?> Function(T old, T excluded)? where})
+      : _usesExcludedTable = true,
+        _where = where == null
+            ? null
+            : ((old, excluded) => Where(where(old, excluded)));
 
   Insertable<D> _createInsertable(TableInfo<T, D> table) {
     return _creator(table.asDslTable, table.createAlias('excluded').asDslTable);

moor/test/insert_test.dart

@@ -205,6 +205,23 @@ void main() {
     ));
   });
 
+  test('can use an upsert clause with where', () async {
+    await db.into(db.todosTable).insert(
+          TodosTableCompanion.insert(content: 'my content'),
+          onConflict: DoUpdate((old) {
+            return TodosTableCompanion.custom(
+                content: const Variable('important: ') + old.content);
+          }, where: (old) => old.category.equals(1)),
+        );
+
+    verify(executor.runInsert(
+      'INSERT INTO todos (content) VALUES (?) '
+      'ON CONFLICT(id) DO UPDATE SET content = ? || content '
+      'WHERE category = ?',
+      argThat(equals(['my content', 'important: ', 1])),
+    ));
+  });
+
   test(
     'can use multiple upsert targets',
     () async {
@@ -236,6 +253,36 @@ void main() {
     },
   );
 
+  test(
+    'can use multiple upsert targets with where',
+    () async {
+      await db
+          .into(db.todosTable)
+          .insert(TodosTableCompanion.insert(content: 'my content'),
+              onConflict: UpsertMultiple([
+                DoUpdate((old) {
+                  return TodosTableCompanion.custom(
+                      content: const Variable('important: ') + old.content);
+                }, where: (old) => old.category.equals(1)),
+                DoUpdate((old) {
+                  return TodosTableCompanion.custom(
+                      content: const Variable('second: ') + old.content);
+                },
+                    target: [db.todosTable.content],
+                    where: (old) => old.category.equals(1)),
+              ]));
+
+      verify(executor.runInsert(
+        'INSERT INTO todos (content) VALUES (?) '
+        'ON CONFLICT(id) DO UPDATE SET content = ? || content '
+        'WHERE category = ? '
+        'ON CONFLICT(content) DO UPDATE SET content = ? || content '
+        'WHERE category = ?',
+        argThat(equals(['my content', 'important: ', 1, 'second: ', 1])),
+      ));
+    },
+  );
+
   test('can use a custom conflict clause', () async {
     await db.into(db.todosTable).insert(
           TodosTableCompanion.insert(content: 'my content'),
@@ -252,6 +299,23 @@ void main() {
     ));
   });
 
+  test('can use a custom conflict clause with where', () async {
+    await db.into(db.todosTable).insert(
+          TodosTableCompanion.insert(content: 'my content'),
+          onConflict: DoUpdate(
+              (old) => TodosTableCompanion.insert(content: 'changed'),
+              target: [db.todosTable.content],
+              where: (old) => old.content.equalsExp(old.title)),
+        );
+
+    verify(executor.runInsert(
+      'INSERT INTO todos (content) VALUES (?) '
+      'ON CONFLICT(content) DO UPDATE SET content = ? '
+      'WHERE content = title',
+      argThat(equals(['my content', 'changed'])),
+    ));
+  });
+
   test('insertOnConflictUpdate', () async {
     when(executor.runInsert(any, any)).thenAnswer((_) => Future.value(3));
 
@@ -284,6 +348,25 @@ void main() {
     ));
   });
 
+  test('can access excluded row in upsert with where', () async {
+    await db.into(db.todosTable).insert(
+          TodosTableCompanion.insert(content: 'content'),
+          onConflict: DoUpdate.withExcluded(
+              (old, excluded) => TodosTableCompanion.custom(
+                    content: old.content + excluded.content,
+                  ),
+              where: (old, excluded) => old.title.equalsExp(excluded.title)),
+        );
+
+    verify(executor.runInsert(
+      'INSERT INTO todos (content) VALUES (?) '
+      'ON CONFLICT(id) DO UPDATE '
+      'SET content = todos.content || excluded.content '
+      'WHERE todos.title = excluded.title',
+      ['content'],
+    ));
+  });
+
   test('applies implicit type converter', () async {
     await db.into(db.categories).insert(CategoriesCompanion.insert(
           description: 'description',

moor/test/integration_tests/insert_integration_test.dart

@@ -47,6 +47,56 @@ void main() {
     expect(row.description, 'original description new description');
   });
 
+  test('insert with DoUpdate and excluded row and where statement true',
+      () async {
+    await db.into(db.categories).insert(
+        CategoriesCompanion.insert(description: 'original description'));
+
+    var row = await db.select(db.categories).getSingle();
+
+    await db.into(db.categories).insert(
+        CategoriesCompanion(
+          id: Value(row.id),
+          priority: const Value(CategoryPriority.medium),
+          description: const Value('new description'),
+        ),
+        onConflict: DoUpdate.withExcluded(
+            (old, excluded) => CategoriesCompanion.custom(
+                description: old.description +
+                    const Constant(' ') +
+                    excluded.description),
+            where: (old, excluded) =>
+                old.priority.isBiggerOrEqual(excluded.priority)));
+
+    row = await db.select(db.categories).getSingle();
+    expect(row.description, 'original description');
+  });
+
+  test('insert with DoUpdate and excluded row and where statement false',
+      () async {
+    await db.into(db.categories).insert(
+        CategoriesCompanion.insert(description: 'original description'));
+
+    var row = await db.select(db.categories).getSingle();
+
+    await db.into(db.categories).insert(
+        CategoriesCompanion(
+          id: Value(row.id),
+          priority: const Value(CategoryPriority.low),
+          description: const Value('new description'),
+        ),
+        onConflict: DoUpdate.withExcluded(
+            (old, excluded) => CategoriesCompanion.custom(
+                description: old.description +
+                    const Constant(' ') +
+                    excluded.description),
+            where: (old, excluded) =>
+                old.priority.isBiggerOrEqual(excluded.priority)));
+
+    row = await db.select(db.categories).getSingle();
+    expect(row.description, 'original description new description');
+  });
+
   test('returning', () async {
     final entry = await db.into(db.categories).insertReturning(
         CategoriesCompanion.insert(description: 'Description'));