diff --git a/src/main/resources/mybatis/tool/GenTableColumnMapper.xml b/src/main/resources/mybatis/tool/GenTableColumnMapper.xml
index 683c95d..536f399 100644
--- a/src/main/resources/mybatis/tool/GenTableColumnMapper.xml
+++ b/src/main/resources/mybatis/tool/GenTableColumnMapper.xml
@@ -41,7 +41,7 @@ PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
     
     <select id="selectDbTableColumnsByName" parameterType="String" resultMap="GenTableColumnResult">
 		 select lower(temp.column_name) as column_name,
-                (case when (temp.nullable = 'N'  and  temp.constraint_type != 'P') then '1' else null end) as is_required,
+                (case when (temp.nullable = 'N'  and  temp.constraint_type != 'P') then '1' else '0' end) as is_required,
                 (case when temp.constraint_type = 'P' then '1' else '0' end) as is_pk,
                 temp.column_id as sort,
                 temp.comments as column_comment,