Microsoft Access压缩表中的多行
我有一个问题，在MS Access 2007中，我希望有人有答案。 我有一个长而简单的表格，其中包含客户名称以及每周交付的日子。 我想总结一下这个表格，把名字和所有的日子列入一个新的字段“ALLDays”，同时保留所有的数据。
源表看起来像这样：
Name Day CustomerA Monday CustomerA Thursday CustomerB Tuesday CustomerB Friday CustomerC Wednesday CustomerC Saturday 我想有一个查询返回这样的结果：
Name ALLDays CustomerA Monday, Thursday CustomerB Tuesday, Friday CustomerC Wednesday, Saturday
谢谢。
通常你必须编写一个函数来允许你创build一个连接列表。 这是我用过的：
Public Function GetList(SQL As String _ , Optional ColumnDelimeter As String = ", " _ , Optional RowDelimeter As String = vbCrLf) As String 'PURPOSE: to return a combined string from the passed query 'ARGS: ' 1. SQL is a valid Select statement ' 2. ColumnDelimiter is the character(s) that separate each column ' 3. RowDelimiter is the character(s) that separate each row 'RETURN VAL: Concatenated list 'DESIGN NOTES: 'EXAMPLE CALL: =GetList("Select Col1,Col2 From Table1 Where Table1.Key = " & OuterTable.Key) Const PROCNAME = "GetList" Const adClipString = 2 Dim oConn As ADODB.Connection Dim oRS As ADODB.Recordset Dim sResult As String On Error GoTo ProcErr Set oConn = CurrentProject.Connection Set oRS = oConn.Execute(SQL) sResult = oRS.GetString(adClipString, -1, ColumnDelimeter, RowDelimeter) If Right(sResult, Len(RowDelimeter)) = RowDelimeter Then sResult = Mid$(sResult, 1, Len(sResult) - Len(RowDelimeter)) End If GetList = sResult oRS.Close oConn.Close CleanUp: Set oRS = Nothing Set oConn = Nothing Exit Function ProcErr: ' insert error handler Resume CleanUp End Function
Remou的版本具有添加的function，您可以传递值的数组而不是SQL语句。
示例查询可能如下所示：
SELECT SourceTable.Name , GetList("Select Day From SourceTable As T1 Where T1.Name = """ & [SourceTable].[Name] & """","",", ") AS Expr1 FROM SourceTable GROUP BY SourceTable.Name;
这是一个不需要VBA的简单解决scheme。 它使用更新查询将值连接到一个字段上。
我将使用我正在使用的示例来显示它。
我有一个表“emails_by_team”，它有两个字段“team_id”和“email_formatted”。 我想要的是收集一个string的给定团队的所有电子邮件。
1）我创build了一个表“team_more_info”，它有两个字段：“team_id”和“team_emails”
2）用“emails_by_team”中的所有“team_id”填充“team_more_info”
3）创build一个更新查询，将“emails_by_team”设置为NULL查询名称：team_email_collection_clear UPDATE team_more_info SET team_more_info.team_emails = Null;
4）这里有个技巧：创build一个查询更新查询名称：team_email_collection_update UPDATE team_more_info INNER JOIN emails_by_team ON team_more_info.team_id = emails_by_team.team_id SET team_more_info.team_emails = IIf（IsNull（[team_emails]），[email_formatted]，[team_emails ]＆“;”＆[email_formatted]）;
5）保持信息最新创build一个macros，在需要时运行这两个查询
第一：team_email_collection_clear
第二：team_email_collection_update
QED
由于这只是一个小范围的select，另一个没有VBA的方法是build立一系列的IIF声明并连接结果。
SELECT name, IIF(SUM(IIF(day = "Monday",1,0)) >0, "Monday, ") & IIF(SUM(IIF(day = "Tuesday",1,0)) >0, "Tuesday, ") & IIF(SUM(IIF(day = "Wednesday",1,0)) >0, "Wednesday, ") & IIF(SUM(IIF(day = "Thursday",1,0)) >0, "Thursday, ") & IIF(SUM(IIF(day = "Friday",1,0)) >0, "Friday, ") & IIF(SUM(IIF(day = "Saturday",1,0)) >0, "Saturday, ") & IIF(SUM(IIF(day = "Sunday",1,0)) >0, "Sunday, ") AS AllDays FROM Table1 GROUP BY name
如果你是一个完美主义者，你甚至可以摆脱这样的最后一个逗号
SELECT name, LEFT( IIF(SUM(IIF(day = "Monday",1,0)) >0, "Monday, ") & IIF(SUM(IIF(day = "Tuesday",1,0)) >0, "Tuesday, ") & IIF(SUM(IIF(day = "Wednesday",1,0)) >0, "Wednesday, ") & IIF(SUM(IIF(day = "Thursday",1,0)) >0, "Thursday, ") & IIF(SUM(IIF(day = "Friday",1,0)) >0, "Friday, ") & IIF(SUM(IIF(day = "Saturday",1,0)) >0, "Saturday, ") & IIF(SUM(IIF(day = "Sunday",1,0)) >0, "Sunday, "), LEN( IIF(SUM(IIF(day = "Monday",1,0)) >0, "Monday, ") & IIF(SUM(IIF(day = "Tuesday",1,0)) >0, "Tuesday, ") & IIF(SUM(IIF(day = "Wednesday",1,0)) >0, "Wednesday, ") & IIF(SUM(IIF(day = "Thursday",1,0)) >0, "Thursday, ") & IIF(SUM(IIF(day = "Friday",1,0)) >0, "Friday, ") & IIF(SUM(IIF(day = "Saturday",1,0)) >0, "Saturday, ") & IIF(SUM(IIF(day = "Sunday",1,0)) >0, "Sunday, ") ) - 2 ) AS AllDays FROM Table1 GROUP BY name
您也可以考虑将它们保留在单独的列中，因为如果从另一个列表中访问此查询，这可能会更有用。 例如，仅在周二查找实例会更容易。 就像是：
SELECT name, IIF(SUM(IIF(day = "Monday",1,0)) >0, "Monday") AS Monday, IIF(SUM(IIF(day = "Tuesday",1,0)) >0, "Tuesday") AS Tuesday, IIF(SUM(IIF(day = "Wednesday",1,0)) >0, "Wednesday") AS Wednesday, IIF(SUM(IIF(day = "Thursday",1,0)) >0, "Thursday") AS Thursday, IIF(SUM(IIF(day = "Friday",1,0)) >0, "Friday") AS Friday, IIF(SUM(IIF(day = "Saturday",1,0)) >0, "Saturday") AS Saturday, IIF(SUM(IIF(day = "Sunday",1,0)) >0, "Sunday") AS Sunday FROM Table1 GROUP BY name
