比较查询

Question

我正在尝试编写一个查询来比较两个日期范围的数据。

第一个日期范围：

select code,description, quantity*each as Total
from orderiteminfo oi, orderinfo o, invoiceinfo i
where oi.orderid = o.orderid
and o.invoiceid = i.invoiceid
and i.invdate between '2014-01-01' and '2014-02-01'
group by oi.code, description, quantity, each

第二个日期范围：

select code,description, quantity*each as Total
from orderiteminfo oi, orderinfo o, invoiceinfo i
where oi.orderid = o.orderid
and o.invoiceid = i.invoiceid
and i.invdate between '2015-01-01' and '2015-02-01'
group by oi.code, description, quantity, each

我希望结果如下：

代码|描述|第一个日期范围的总计|第二个日期范围的总计

Answer 1

像这样的东西

all

作为旁注，总是使用all语法来连接两个表而不是旧式逗号分隔连接，并将过滤器单独保留在SELECT code, description, SUM(CASE WHEN i.invdate BETWEEN '2014-01-01' AND '2014-02-01' THEN quantity * each END) AS [Total for First Date Range], SUM(CASE WHEN i.invdate BETWEEN '2015-01-01' AND '2015-02-01' THEN quantity * each END) AS [Total for second Date Range] FROM orderiteminfo oi INNER JOIN orderinfo o ON oi.orderid = o.orderid INNER JOIN invoiceinfo i ON o.invoiceid = i.invoiceid WHERE ( i.invdate BETWEEN '2014-01-01' AND '2014-02-01' OR i.invdate BETWEEN '2015-01-01' AND '2015-02-01' ) GROUP BY oi.code, description 子句中，这更易于阅读

Answer 2

如果我理解正确，我认为您宁愿使用case when语句在单个查询中执行此操作：

select code,
       description, 
       case 
          when i.invdate between '2014-01-01' and '2014-02-01'
            then quantity*each 
        end  Total_for_First_Date_Range,
        case 
          when i.invdate between '2015-01-01' and '2015-02-01'
            then quantity*each 
        end  Total_for_Second_Date_Range              
from orderiteminfo oi, orderinfo o, invoiceinfo i
where oi.orderid = o.orderid
and o.invoiceid = i.invoiceid 
group by oi.code, description, quantity, each; --not sure if you need this