diff --git a/dl-module-jx/src/main/resources/mapper/course/SchoolCourseOrderMapper.xml b/dl-module-jx/src/main/resources/mapper/course/SchoolCourseOrderMapper.xml
index 3fd4db68..fb745f44 100644
--- a/dl-module-jx/src/main/resources/mapper/course/SchoolCourseOrderMapper.xml
+++ b/dl-module-jx/src/main/resources/mapper/course/SchoolCourseOrderMapper.xml
@@ -56,7 +56,7 @@
                         AND main.discount > 0
                     </when>
                     <when test="entity.discountIndex == 0">
-                        AND main.discount = 0 or main.discount is null
+                        AND (main.discount = 0 or main.discount IS NULL)
                     </when>
                 </choose>
             </if>