修改

blade-service/blade-client/src/main/java/org/springblade/client/school/mapper/SchoolConfigItemMapper.xml

@@ -57,7 +57,7 @@
             AND cf.class_type = #{classType}
         </if>
         <if test="classType==null and classType == ''">
-            AND cf.class_type = ''
+            AND cf.class_type IS NULL
         </if>
 	    ORDER BY ci.salary DESC LIMIT 1
     </select>