修复调差新建一期bug

app/service/material_list.js

@@ -232,7 +232,7 @@ module.exports = app => {
             for (const ml of materialListData) {
                 // 获取小计值
                 let gather_qty = null;
-                if (ml.mx_id !== null) {
+                if (ml.mx_id !== null && ml.mx_id !== '') {
                     gather_qty = await this.ctx.service.stagePos.getGatherQtyByMaterial(ml.tid, newMaterial.stage_id, ml.gcl_id, ml.mx_id);
                 } else {
                     gather_qty = await this.ctx.service.stageBills.getGatherQtyByMaterial(ml.tid, newMaterial.stage_id, ml.gcl_id);