fix (mssql): bulkUpdate returning values

lib/dialects/mssql/query.js

@@ -210,7 +210,11 @@ class Query extends AbstractQuery {
       return data[0];
     }
     if (this.isBulkUpdateQuery()) {
-      return data.length;
+      if (this.options.returning) {
+        return this.handleSelectQuery(data);
+      }
+
+      return rowCount;
     }
     if (this.isBulkDeleteQuery()) {
       return data[0] && data[0].AFFECTEDROWS;

test/integration/model/update.test.js

@@ -139,6 +139,25 @@ describe(Support.getTestDialectTeaser('Model'), () => {
       });
     }
 
+    if (_.get(current.dialect.supports, 'returnValues.output')) {
+      it('should output the updated record', function() {
+        return this.Account.create({ ownerId: 2 }).then(account => {
+          return this.Account.update({ name: 'FooBar' }, {
+            where: {
+              id: account.get('id')
+            },
+            returning: true
+          }).then(([, accounts]) => {
+            const firstAcc = accounts[0];
+            expect(firstAcc.name).to.be.equal('FooBar');
+            return firstAcc.reload();
+          }).then(accountReloaded => {
+            expect(accountReloaded.ownerId, 'Reloaded as output update only return primary key and changed fields').to.be.equal(2);
+          });
+        });
+      });
+    }
+
     if (current.dialect.supports['LIMIT ON UPDATE']) {
       it('should only update one row', function() {
         return this.Account.create({

types/lib/model.d.ts

@@ -2043,7 +2043,7 @@ export abstract class Model<T = any, T2 = any> extends Hooks {
   /**
    * Update multiple instances that match the where options. The promise returns an array with one or two
    * elements. The first element is always the number of affected rows, while the second element is the actual
-   * affected rows (only supported in postgres with `options.returning` true.)
+   * affected rows (only supported in postgres and mssql with `options.returning` true.)
    */
   public static update<M extends Model>(
     this: { new (): M } & typeof Model,