VB.NET错误：操作数类型冲突：日期与int不兼容 [英] VB.NET Error: Operand type clash: date is incompatible with int

问题描述

我正在尝试使用where子句从数据库中显示名为staffpresentee的表中的记录...



i am using visual studio 2010 ...



表设计如下 -

      fieldname       ;            数据类型          允许为空

1     staff_id（FK）              数字（18,0）        是

2      日期       &NBSP ;                   日期     &NBSP ;           no

3   &nbs磷;本                       焦炭（ 1）              yes



注意类型第二个字段是日期而不是日期时间......



我想显示表中所有日期都在''日期'的记录字段...

我当前的查询是 -



cmd =新的SqlClient.SqlCommand（select * from staffpresentee where date =& Date.Now.Date，cn）

dr = cmd.ExecuteReader



for dr = cmd.ExecuteReader我收到错误操作数类型冲突：日期与int不兼容



i尝试select * from staffpresentee查询而没有正确运行的where子句...

解决方案

两个问题：

1）date是一个SQL保留字，所以叫你的co lumn总会给出问题。

2）将日期作为参数发送而不是连接字符串 - 这总是一个更好的主意，因为它也避免了SQL注入攻击。

 cmd = 新 SqlCommand（  select * from staffpresentee，其中[date] = @ DT，cn）
 cmd.Parameters.AddWithValue（ < span class =code-string> @ DT，DateTime.Now。 Date ）
 dr = cmd.ExecuteReader（）

I am trying to display records from a table named staffpresentee from a database using the where clause...

i am using visual studio 2010...

the table design is as follows-
     fieldname                  datatype          allownull
1    staff_id (fk)              numeric(18,0)       yes
2      date                           date                no
3    present                       char(1)             yes

Note that the type of the 2nd field is date and not datetime...

I want to display all records from the table that have today''s date int the ''date'' field...
My current query is-

cmd = New SqlClient.SqlCommand("select * from staffpresentee where date=" & Date.Now.Date, cn)
dr = cmd.ExecuteReader

for dr = cmd.ExecuteReader i get the error "Operand type clash: date is incompatible with int"

i tried the select * from staffpresentee query without the where clause it runs correctly...

解决方案

Two problems:
1) "date" is an SQL reserved word, so calling your column that is always going to give problems.
2) Send the date as a parameter rather that concatenating strings - that is always a better idea as it avoids SQL injection attacks as well.

cmd = New SqlCommand("select * from staffpresentee where [date]=@DT", cn)
cmd.Parameters.AddWithValue("@DT", DateTime.Now.Date)
dr = cmd.ExecuteReader()

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