fix: 大梦到mysql数据库迁移

bound-link-api/sa-flow-common/src/main/java/com/cloud/sa/flow/commom/service/genSql/impl/GeneratorSqlForSqlServer.java

@@ -141,7 +141,7 @@ public class GeneratorSqlForSqlServer implements SqlGeneratorService {
     }
 
     public String getMaxSortIndex(String tableName, String mainTableId) {
-        return "SELECT ifnull(max(sort_index),0) maxIndex FROM " + tableName + " WHERE flow_parent_id='" + mainTableId + "'";
+        return "SELECT isnull(max(sort_index),0) maxIndex FROM " + tableName + " WHERE flow_parent_id='" + mainTableId + "'";
     }
 
     public String getDeleteSql(String tableName, String objectId) {