Question

|ID      |AN      |CRN      |CRT      |SD       |ED 
+-------------------------------------------------------------------
|1       |a       |x        |R        |01-Aug-10| 09-Sep-10
|1       |a       |y        |R        |10-Sep-10| 08-Dec-10 
|1       |a       |z        |R        |20-Dec-10| 
|1       |a       |z        |S        |01-Aug-10| 31-Jan-10
|1       |a       |v        |S        |01-Feb-10| 
|2       |b       |d        |S        |01-Aug-10| 29-Aug-10
|2       |b       |d        |S        |31-Aug-10|

这是我从上表中寻找的东西。我希望得到sd和ed之间的区别。查询应该看看ID是否相同，如果它是相同的那么它应该看起来CRT是相同的，如果它们是相同的那么它应该显示差异，否则它应该为0，所以查询需要检查每一行..现在如果帐户不同，则查询应默认显示为0。

所以结果应该显示类似的东西

|ID      |AN      |CRN      |CRT      |SD       |ED         |Difference
+-------------------------------------------------------------------
|1       |a       |x        |R        |01-Aug-10| 09-Sep-10 |0 *(since this is 1st entry in respect to the CRT within the same ID)*
|1       |a       |y        |R        |10-Sep-10| 08-Dec-10 |1 *(10sept(SD)-9sept(ED))*
|1       |a       |z        |R        |20-Dec-10|           |12 
|1       |a       |z        |S        |01-Aug-10| 31-Jan-10 |0 *(since this is 1st entry in respect to the CRT within the same ID)*
|1       |a       |v        |S        |01-Feb-10|           |1 *(1Feb(SD)-31Jan(ED))*
|2       |b       |d        |S        |01-Aug-10| 29-Aug-10 |0 *(since this is a new ID)*
|2       |b       |d        |S        |31-Aug-10|           |2

在differenc col中我只需要没有（）中提到的旁白的差异。请帮忙......

Answer 1

获得此更正的关键是使表具有与您的行顺序相匹配的顺序（自动编号）键。如果您的表上还没有类似的键，则需要将值插入到新的临时表中，并将自动编号字段作为键。我已经在一个名为MyTable的表中使用名为TempID的自动编号键。

然后，您需要使用以下定义创建名为PreviousRow的查询：

SELECT [TempID]+1 AS PreviousTempID, MyTable.ID, MyTable.AN, MyTable.CRN, MyTable.CRT, MyTable.SD, MyTable.ED FROM MyTable;

然后您的结果是以下查询：

SELECT MyTable.ID, MyTable.AN, MyTable.CRN, MyTable.CRT, MyTable.SD, MyTable.ED, IIf([MyTable.ID]=[PreviousRow.ID] And [MyTable.CRT]=[PreviousRow.CRT],DateDiff("d",[PreviousRow.ED],[MyTable.SD]),0) AS Difference FROM MyTable LEFT JOIN PreviousRow ON MyTable.TempID = PreviousRow.PreviousTempID;

同一个表中行的日期之间的差异

1 个答案: