Join update fix

src/Sql/Update.php

@@ -187,7 +187,18 @@ protected function processSet(
     ) {
         $setSql = [];
         foreach ($this->set as $column => $value) {
-            $prefix = $platform->quoteIdentifier($column) . ' = ';
+            $prefix = $this->resolveColumnValue(
+                [
+                    'column'       => $column,
+                    'fromTable'    => '',
+                    'isIdentifier' => true,
+                ],
+                $platform,
+                $driver,
+                $parameterContainer,
+                'column'
+            );
+            $prefix .= ' = ';
             if (is_scalar($value) && $parameterContainer) {
                 $setSql[] = $prefix . $driver->formatParameterName($column);
                 $parameterContainer->offsetSet($column, $value);

test/Sql/UpdateTest.php

@@ -391,6 +391,32 @@ public function testJoin()
         );
     }
 
+    /**
+     * Here test if we want update fields from specific table.
+     * Important when we're updating fields that are existing in several tables in one query.
+     * The same test as above but here we will specify table in update params
+     */
+    public function testJoinMultiUpdate()
+    {
+        $this->update->table('Document');
+        $this->update->set(['Documents.x' => 'y'])
+            ->join(
+                'User',
+                'User.UserId = Document.UserId'
+            )
+            ->join(
+                'Category',
+                'Category.CategoryId = Document.CategoryId',
+                Join::JOIN_LEFT
+            );
+
+        self::assertEquals(
+            'UPDATE "Document" INNER JOIN "User" ON "User"."UserId" = "Document"."UserId" '
+            . 'LEFT JOIN "Category" ON "Category"."CategoryId" = "Document"."CategoryId" SET "Documents"."x" = \'y\'',
+            $this->update->getSqlString(new TrustingSql92Platform())
+        );
+    }
+
     /**
      * @testdox unit test: Test join() returns Update object (is chainable)
      * @covers \Zend\Db\Sql\Update::join