需要关于 JOIN 和 Condition 的帮助答案

【问题标题】：Need help on JOIN and Condition需要关于 JOIN 和 Condition 的帮助
【发布时间】：2016-02-10 14:24:59
【问题描述】：

客户表：

customerId  customerName    startTime   projectDateOfCompletion
1            ANZ             2015-12-05       NULL
2            Barklays        2015-11-25     2016-02-10
3            Grindlays       2016-02-06       NULL

报告表：

customerId  repId   fromDateTime    toDateTim
1           1       2015-12-05      2016-02-05
1           2       2016-02-06         NULL
2           3       2015-11-25      2016-02-10
3           1       2016-02-08         NULL

客户支持表：

repId   customerSupportRep
1       Jim Daniel      
2       Mark Chad       
3       Juan Maximo

不确定如何以表格形式格式化表格。希望看起来像桌子。我正在寻求有关以下查询的帮助

SELECT 
    t.customerName AS 'Customer Name', 
    u.customerSupportRep AS 'Customer   Support Representative', 
    t.startTime AS 'Start Date/Time'
FROM Customer t
    JOIN CustomerSupport u 
        ON u.repId = ( SELECT repId 
                       FROM Reports 
                       WHERE  
                            customerId = t.customerId AND  
                            (CASE 
                                WHEN (@archiveStartTime IS NOT NULL )
                                    then  @archiveStartTime BETWEEN fromDateTime AND toDateTime
                                ELSE toDateTime IS NULL 
                            END)
                    )                        
    WHERE 
        t.projectDateOfCompletion IS NULL OR 
        t.projectDateOfCompletion = '';

如果@archiveStartTime 为NULL，我想要projectDateOfCompletion 为NULL 的记录如果@archiveStartTime 不为NULL，那么我想列出@archiveStartTime 位于fromDateTime 和toDateTime 之间且projectDateOfCompletion 为NULL 的所有记录。

任何帮助将不胜感激。

【问题讨论】：

标签： sql if-statement join case

【解决方案1】：

试试这个：

`SELECT t.customerName AS 'Customer Name', u.customerSupportRep AS 'Customer   Support Representative', t.startTime AS 'Start Date/Time'
FROM Customer t
    JOIN CustomerSupport u ON u.repId = ( SELECT repId FROM Reports WHERE  customerId = t.customerId AND  
        ((@archiveStartTime IS NOT NULL
          and @archiveStartTime BETWEEN fromDateTime AND toDateTime)
        or (@archiveStartTime IS NULL AND toDateTime IS NULL )
        ) )
    WHERE t.projectDateOfCompletion IS NULL OR t.projectDateOfCompletion = '';`

查询很难阅读，所以也许我把条件写错了。我的想法是：而不是你在那里做的情况，使用 OR 像这样（如果查询没有运行，你自己调整它而不是情况）

AND  
        ((@archiveStartTime IS NOT NULL
          and @archiveStartTime BETWEEN fromDateTime AND toDateTime)
        or (@archiveStartTime IS NULL AND toDateTime IS NULL ))

【讨论】：

【解决方案2】：

@Mureinik 的此查询
从我的表中选择 * 当 id = 12345 AND ((TermDate IS NULL AND getdate() BETWEEN StartDate AND DATEADD(dd, 30, StartDate)) 或 GETDATE()

来自Add Case Statement in Where Clause 帮助解决了这个问题。谢谢@Mureinik

【讨论】：