fix: 旧库存进行判空处理

gongchunyi

昨天 83bfb1d99f351371a720c270f20d1eaff0f9d9bc

 src/main/java/com/ruoyi/purchase/service/IPurchaseLedgerService.java

@@ -43,4 +43,6 @@
    String getPurchaseNo();

    AjaxResult importData(MultipartFile file);

    PurchaseLedgerDto getPurchaseByCode(PurchaseLedgerDto purchaseLedgerDto);
}