教材征订线上BUG：按班级征订时：1、征订的教材不是根据所选班级获取的全部教材（不同班级相同教材要去重，只是数量相加）；2、征订数量不是根据教材有使用班级的数量相加；

src/main/resources/mapper/textbook/TextbookMapper.xml

@@ -344,7 +344,7 @@
     <select id="getSubscriptionPageByClass"
             parameterType="com.xjrsoft.module.textbook.dto.TextbookSubscriptionListDto"
             resultType="com.xjrsoft.module.textbook.vo.TextbookSubscriptionListVo">
-        SELECT t3.id, t3.id AS textbookId, t2.name AS courseName, t3.issn, t3.book_name,
+        SELECT distinct t3.id, t3.id AS textbookId, t2.name AS courseName, t3.issn, t3.book_name,
         t3.publishing_house, t3.editor_in_chief, t3.course_subject_id, t3.version,
         t3.textbook_type, t3.use_type FROM base_class_course t
         LEFT JOIN base_class t1 ON (t1.id = t.class_id)