PostgreSQL group by 子句中，如何在特定列中保留一条记录，并使其他记录值为0？

Question

我有这样一组数据

结果应该是这样的

我的查询

SELECT max(pi.pi_serial) AS proforma_invoice_id,
       max(mo.manufacturing_order_master_id) AS manufacturing_order_master_id,
       max(pi.amount_in_local_currency) AS sales_value,
FROM proforma_invoice pi
JOIN schema_order_map som ON pi.pi_serial = som.pi_id
LEFT JOIN manufacturing_order_master mo ON som.mo_id = mo.manufacturing_order_master_id
WHERE to_date(pi.proforma_invoice_date, 'DD/MM/YYYY') BETWEEN to_date('01/03/2021', 'DD/MM/YYYY') AND to_date('19/04/2021', 'DD/MM/YYYY')
  AND pi.pi_serial in (9221,
                       9299)
GROUP BY mo.manufacturing_order_master_id,
         pi.pi_serial
ORDER BY pi.pi_serial

Answer 1

选项 1：在 Crystal 报告中创建一个“运行总计”字段，以便每个“proforma_invoice_id”仅汇总一个“sales_value”。

选项 2：向您的 Postgresql 查询添加一个辅助列，如下所示：

case 
    when row_number() 
         over (partition by proforma_invoice_id 
               order by manufacturing_order_master_id) 
         = 1 
then sales_value 
else 0 
end 
    as sales_value

我为您准备了 this SQLFiddle 示例（当然也希望鼓励您对下一个关于 SO 的数据库查询相关问题做同样的事情:-)

PostgreSQL group by 子句中，如何在特定列中保留一条记录，并使其他记录值为0？

How to keep one record in specific column and make other record value 0 in group by clause in PostgreSQL?

postgresql

crystal-reports