在 T-SQL 查询 UNION、JOINS、COUNT 方面需要帮助答案

【问题标题】：Need assistance with T-SQL query UNION, JOINS, COUNT在 T-SQL 查询 UNION、JOINS、COUNT 方面需要帮助
【发布时间】：2016-12-12 05:06:02
【问题描述】：

看起来我很难通过查询来汇总按联合运营商分组的货物。今天我正在检索由代理、司机 (U.AgentCode) 运送到特定国家 (U.CtryCode、U.CtryName) 的总出货量 (count(Distinct. U.SjipmentId)。我最不想做的事情是将所有出货量相加得到出货总量。有人会建议我如何以简单易行的方式实现这一目标吗？您可以在下面找到我最新的查询。

SELECT U.AgentCode, U.CtryCode, U.CtryName, count(distinct U.Id)
    FROM (
    select Agent.AgentCode, Addr.CtryCode, Ctry.Name, Ship.Id
    from Shipment
    LEFT JOIN RouteTab (nolock) ON RoutTbl.Cexp= Shipment.ID  
    LEFT JOIN Agent (NOLOCK) ON Agent.AgentID = RouteTbl.AgentID
    LEFT JOIN Addr (NOLOCK) ON Addr.AddrId = Shipment.AddrId
    LEFT JOIN Ctry (NOLOCK) ON Ctry.Id = Addr.Id
    WHERE RouteTbl.Bur ='GB01' AND Agent.AgentCode IS NOT NULL
    Union ALL
    select Driver.DriverCode, Addr.CtryCode, Ctry.Name, Shipment.Id
    from Shipment
    LEFT JOIN RouteTab (nolock) ON RoutTbl.Cexp= Shipment.Id
    LEFT JOIN Driver (NOLOCK) ON Driver.DriverId = RouteTbl.DriverId
    LEFT JOIN Addr (NOLOCK) ON Addr.AddrId = Shipment.AddrId
    LEFT JOIN Ctry (NOLOCK) ON Ctry.Id = Addr.Id
    WHERE RouteTbl.Bur ='GB01' AND Driver.DriverCode IS NOT NULL
    )  as U 
GROUP BY U.AgentCode, U.CtryCode, U.CtryName
ORDER BY U.AgentCode, U.CtryCode, U.CtryName

【问题讨论】：

Count number of records returned by group by的可能重复
还有这个：stackoverflow.com/questions/12927268/…

标签： sql sql-server tsql

【解决方案1】：

Union 语句需要具有完全相同的列名，在您的 Union All 命令下方的代码中，试试这个：

select Driver.DriverCode as AgentCode, Addr.CtryCode, Ctry.Name, Shipment.Id

还要在两个 select 语句中将 Ctry.Name 更改为 Ctry.Name as CtryName。

【讨论】：

【解决方案2】：

您的UNION 有相同的代码。使用WITH 子句的好方法。在您的select 中，您不需要UNION - 使用左连接和COALESCE。

;With r_tab AS
(
select RouteTab.AgentID, Addr.CtryCode, Ctry.Name, Ship.Id,RouteTab.DriverId
    from Shipment
    LEFT JOIN RouteTab (nolock) ON RouteTab.Cexp= Shipment.ID 
    LEFT JOIN Addr (NOLOCK) ON Addr.AddrId = Shipment.AddrId
    LEFT JOIN Ctry (NOLOCK) ON Ctry.Id = Addr.Id
    WHERE RouteTab.Bur ='GB01'
)
SELECT COALESCE(Agent.AgentCode,Driver.DriverCode) AgentCode, U.AgentCode, U.CtryCode, U.CtryName,
       count(distinct U.Id)
    FROM r_tab U
    LEFT JOIN Agent (NOLOCK) ON Agent.AgentID = U.AgentID
       AND Agent.AgentCode IS NOT NULL
    LEFT JOIN Driver (NOLOCK) ON Driver.DriverId = U.DriverId
       AND Driver.DriverCode IS NOT NULL
GROUP BY COALESCE(Agent.AgentCode,Driver.DriverCode), U.CtryCode, U.CtryName
ORDER BY U.AgentCode, U.CtryCode, U.CtryName`enter code here`

【讨论】：