C# Linq where 子句只比较日期值而不比较时间值
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Linq where clause compare only date value without time value
提问by Frank Myat Thu
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true
&& x.DateTimeValueColumn <= DateTime.Now)
.Select(x => x);
Upper query is working correct.
But I want to check only date value only.
But upper query check date + time value.
上层查询工作正常。
但我只想检查日期值。
但上查询检查日期+时间值。
In traditional mssql, I could write query like below.
在传统的 mssql 中，我可以编写如下查询。
SELECT * FROM dbo.tbl_MyTable
WHERE
CAST(CONVERT(CHAR(10), DateTimeValueColumn, 102) AS DATE) <=
CAST(CONVERT(CHAR(10),GETDATE(),102) AS DATE)
AND
Active = 1
So could anyone give me suggestion how could I check only date value in Linq.
那么任何人都可以给我建议如何只检查 Linq 中的日期值。
采纳答案by Johann Blais
There is also EntityFunctions.TruncateTimeor DbFunctions.TruncateTimein EF 6.0
还有EntityFunctions.TruncateTime或DbFunctions.TruncateTime在 EF 6.0
回答by Pranay Rana
EDIT
编辑
To avoid this error : The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported.
为避免此错误：LINQ to Entities 中不支持指定的类型成员“Date”。仅支持初始值设定项、实体成员和实体导航属性。
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true)
.Select(x => x).ToList();
var filterdata = _My_ResetSet_Array
.Where(x=>DateTime.Compare(x.DateTimeValueColumn.Date, DateTime.Now.Date) <= 0 );
The second line is required because LINQ to Entity is not able to convert date property to sql query. So its better to first fetch the data and then apply the date filter.
第二行是必需的，因为 LINQ to Entity 无法将日期属性转换为 sql 查询。所以最好先获取数据，然后应用日期过滤器。
EDIT
编辑
If you just want to compare the date value of the date time than make use of
如果您只想比较日期时间的日期值而不是使用
DateTime.DateProperty- Gets the date component of this instance.
DateTime.Date属性- 获取此实例的日期组件。
Code for you
给你的代码
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true
&& DateTime.Compare(x.DateTimeValueColumn.Date, DateTime.Now.Date) <= 0 )
.Select(x => x);
If its like that then use
如果它像那样然后使用
DateTime.Compare Method- Compares two instances of DateTime and returns an integer that indicates whether the first instance is earlier than, the same as, or later than the second instance.
DateTime.Compare 方法- 比较DateTime 的两个实例并返回一个整数，指示第一个实例是早于、相同还是晚于第二个实例。
Code for you
给你的代码
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true
&& DateTime.Compare(x.DateTimeValueColumn, DateTime.Now) <= 0 )
.Select(x => x);
Example
例子
DateTime date1 = new DateTime(2009, 8, 1, 0, 0, 0);
DateTime date2 = new DateTime(2009, 8, 1, 12, 0, 0);
int result = DateTime.Compare(date1, date2);
string relationship;
if (result < 0)
relationship = "is earlier than";
else if (result == 0)
relationship = "is the same time as";
else
relationship = "is later than";
回答by igrimpe
Use mydate.Dateto work with the date part of the DateTime class only.
仅mydate.Date用于处理 DateTime 类的日期部分。
回答by Pranay Rana
Simple workaround to this problem to compare date part only
此问题的简单解决方法是仅比较日期部分
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true &&
x.DateTimeValueColumn.Year == DateTime.Now.Year
&& x.DateTimeValueColumn.Month == DateTime.Now.Month
&& x.DateTimeValueColumn.Day == DateTime.Now.Day);
Because 'Date' datatype is not supported by linq to entity , where as Year, Month and Day are 'int' datatypes and are supported.
因为 linq to entity 不支持 'Date' 数据类型，而 Year、Month 和 Day 是 'int' 数据类型并且受支持。
回答by Joe Stellato
&& x.DateTimeValueColumn <= DateTime.Now
&& x.DateTimeValueColumn <= DateTime.Now
This is supported so long as your schema is correct
只要您的架构正确，就支持此操作
&& x.DateTimeValueColumn.Value.Date <=DateTime.Now
回答by takemyoxygen
In similar case I used the following code:
在类似的情况下，我使用了以下代码：
DateTime upperBound = DateTime.Today.AddDays(1); // If today is October 9, then upperBound is set to 2012-10-10 00:00:00
return var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true
&& x.DateTimeValueColumn < upperBound) // Accepts all dates earlier than October 10, time of day doesn't matter here
.Select(x => x);
回答by Jatin
result = from r in result where (r.Reserchflag == true &&
(r.ResearchDate.Value.Date >= FromDate.Date &&
r.ResearchDate.Value.Date <= ToDate.Date)) select r;
回答by Soharab Shaikh
Working code :
工作代码：
{
DataBaseEntity db = new DataBaseEntity (); //This is EF entity
string dateCheck="5/21/2018";
var list= db.tbl
.where(x=>(x.DOE.Value.Month
+"/"+x.DOE.Value.Day
+"/"+x.DOE.Value.Year)
.ToString()
.Contains(dateCheck))
}
回答by Karthic G
Try this,
尝试这个，
var _My_ResetSet_Array = _DB
.tbl_MyTable
.Where(x => x.Active == true
&& x.DateTimeValueColumn <= DateTime.Now)
.Select(x => x.DateTimeValueColumn)
.AsEnumerable()
.select(p=>p.DateTimeValueColumn.value.toString("YYYY-MMM-dd");
回答by Roberto Mutti
Do not simplify the code to avoid "linq translation error": The test consist between a date with time at 0:0:0 and the same date with time at 23:59:59
不要简化代码以避免“linq 翻译错误”：测试包括时间为 0:0:0 的日期和时间为 23:59:59 的同一日期
iFilter.MyDate1 = DateTime.Today; // or DateTime.MinValue
// GET
var tempQuery = ctx.MyTable.AsQueryable();
if (iFilter.MyDate1 != DateTime.MinValue)
{
TimeSpan temp24h = new TimeSpan(23,59,59);
DateTime tempEndMyDate1 = iFilter.MyDate1.Add(temp24h);
// DO not change the code below, you need 2 date variables...
tempQuery = tempQuery.Where(w => w.MyDate2 >= iFilter.MyDate1
&& w.MyDate2 <= tempEndMyDate1);
}
List<MyTable> returnObject = tempQuery.ToList();
