# 案例："Row () Expression" can not be shipped
#### 问题根因
语句中有row表达式，一般表现为在targetlist（输出列SELECT 和 FROM之间）上存在括号表达式"(......)"，
**处理方案**：改写SQL，消除row表达式。
#### 案例1：row表达式(k4.businessID, arriveDate)出现在targetlist中
**原始语句**
```
SELECT
    date_format(arriveDate, '%Y-%m-%d') AS "date",
    sales,
    COUNT(DISTINCT (k4.businessID, arriveDate)/*row expression*/)
FROM (
    SELECT k1.businessID, k2.arriveDate, k1.sales
    FROM potential_customers k1
    LEFT JOIN flow_reception k2
        ON k1.businessID = k2.businessID
    WHERE k2.arriveDate BETWEEN '2024-08-31' AND '2024-09-02'
) k4
GROUP BY arriveDate, sales;
```
![](https://support.huaweicloud.com/devg-911-dws/figure/zh-cn_image_0000002526265757.png "点击放大")
**规避方案**：不直接输出row表达式，因此改写row表达式为字符串拼接。
```
SELECT
    date_format(arriveDate, '%Y-%m-%d') AS "date",
    sales,
    COUNT(DISTINCT k4.businessID ||'-' ||  arriveDate/*Eliminate row expressions*/)
FROM (
    SELECT k1.businessID, k2.arriveDate, k1.sales
    FROM potential_customers k1
    LEFT JOIN flow_reception k2
        ON k1.businessID = k2.businessID
    WHERE k2.arriveDate BETWEEN '2024-08-31' AND '2024-09-02'
) k4
GROUP BY arriveDate, sales;
```
![](https://support.huaweicloud.com/devg-911-dws/figure/zh-cn_image_0000002526306787.png "点击放大")
**修改点对比**
![](https://support.huaweicloud.com/devg-911-dws/figure/zh-cn_image_0000002526307817.png "点击放大")