Question

以下查询不会返回任何值。

SELECT o.ea_guid as CLASSGUID, o.Object_Type as CLASSTYPE, 
       o.Name, type.Property, type.Value
FROM ((t_object as o
       INNER JOIN t_objectproperties as location
         ON o.Object_ID = location.Object_ID)
       INNER JOIN t_objectproperties as type 
         ON o.Object_ID = type.Object_ID)
WHERE location.Property = 'Location' 
  AND location.Value = 'ND'
  AND type.Property = 'FDate'
  AND CDate(type.Value) >= CDate('21/02/2014') 
  AND CDate(type.Value) <= CDate('24/02/2014')

但是，如果我执行以下操作，则会返回一组不在所需范围之间的结果

SELECT o.ea_guid as CLASSGUID, o.Object_Type as CLASSTYPE, 
     o.Name, type.Property, type.Value
  FROM ((t_object as o
         INNER JOIN t_objectproperties as location
           ON o.Object_ID = location.Object_ID)
         INNER JOIN t_objectproperties as type 
           ON o.Object_ID = type.Object_ID)
  WHERE location.Property = 'Location' 
    AND location.Value = 'ND'
    AND type.Property = 'FDate'
    AND type.Value >= CDate('21/02/2014') 
    AND type.Value <= CDate('24/02/2014')

我还尝试使用BETWEEN并返回范围之外的结果。

SELECT o.ea_guid as CLASSGUID, o.Object_Type as CLASSTYPE, 
       o.Name, type.Property, type.Value
    FROM ((t_object as o
           INNER JOIN t_objectproperties as location
             ON o.Object_ID = location.Object_ID)
           INNER JOIN t_objectproperties as type 
             ON o.Object_ID = type.Object_ID)
    WHERE location.Property = 'Location' 
      AND location.Value = 'ND'
      AND type.Property = 'FDate'
      AND type.Value BETWEEN CDate('21/02/2014') 
      AND <= CDate('24/02/2014')

Answer 1

日期字符串的问题是01/02/2014之类的日期可以解释为dd/MM/yyyy或MM/dd/yyyy。更好地以反向格式存储日期：yyyy/MM/dd。我从未见过像yyyy/dd/MM这样的格式。因此，对于日期和月份的混淆应该是安全的。

反向格式的另一个优点是其字符串表示与其日期表示的方式相同。即以yyyy/MM/dd格式排序字符串会产生正确的顺序。因此，没有必要将它们转换为比较日期。

尝试选择Month(CDate(type.Value))并查看这是否真的总是会返回几个月，或者是否有时会返回几天。如果返回天数，您可以尝试转换像这样的属性

DateSerial(Mid$(type.Value, 7)  , Mid$(type.Value, 4, 2), Mid$(type.Value, 1, 2))

Answer 2

所以，我尝试了这个，它起作用了。您可以将type.Value转换为日期，然后将Format()转换为短日期，并按原样传递参数。无需弄乱Access无法真正关心的日期格式。只需格式化即可。

SELECT t1.ID, t1.dateString
FROM Table1 AS t1
WHERE Format(CDate(t1.dateString), "Short Date") < Format(#03/31/2014#, "Short Date");

dateString是一个文本字段（就像你说的那样），我测试过的值是：

+-------------+
|  10/01/2014 |
+-------------+
|  20/02/2014 |
+-------------+
|  31/03/2014 |
+-------------+

以下是使用BETWEEN的SQL：

   SELECT t1.ID, t1.dateString
FROM Table1 AS t1
WHERE Format(CDate(t1.dateString), "Short Date")
 Between
               Format(#03/30/2014#, "Short Date")
 AND  
               Format(#01/01/2014#, "Short Date")

在Microsoft Access日期之间搜索时出现问题

2 个答案: