bug fixed for sql parser nchar literal support. for issue #2558

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -474,6 +474,7 @@ public class Lexer {
             }
 
             if (c1 == '\'') {
+                bufPos = 0;
                 ++pos;
                 ch = '\'';
                 scanString();

src/test/java/com/alibaba/druid/bvt/sql/sqlserver/SQLServerUpdateTest6.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 1999-2017 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.sqlserver;
+
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.sqlserver.parser.SQLServerStatementParser;
+import junit.framework.TestCase;
+
+public class SQLServerUpdateTest6 extends TestCase {
+
+    public void test_update() throws Exception {
+        String sql = "update clients set name =N'小明',age =1";
+
+        String expect = "UPDATE TOP (10) HumanResources.Employee"
+                + "\nSET VacationHours = VacationHours * 1.25, ModifiedDate = GETDATE()"
+                + "\nOUTPUT inserted.BusinessEntityID, deleted.VacationHours, inserted.VacationHours, inserted.ModifiedDate"
+                + "\n\tINTO @MyTableVar;";
+        
+
+        SQLServerStatementParser parser = new SQLServerStatementParser(sql);
+        SQLStatement stmt = parser.parseStatementList().get(0);
+
+        assertEquals("UPDATE clients\n" +
+                "SET name = N'小明', age = 1", stmt.toString());
+    }
+}