Question

我试图创建一个动态SQL查询，但不幸的是它显示错误：

Msg 245，Level 16，State 1，Line 14
从SimulationVisit SV内部联接学生转换varchar值'select count（s.ID），count（distinct（s.ID））时转换失败。 ID = SV。 AC上的学生ID内部联接活动上下文AC。 ID = SV。 ActivityContextID WHERE（AC.TenantID ='to data type int。

我的代码

declare @DateRangeStart    [DATETIME2](7), 
        @DateRangeEnd      [DATETIME2](7), 
        @TenantID          [SMALLINT] , 
        @ActivityContextID [INT], 
        @StudentID         [INT] = NULL 

'select count(s.ID),count(distinct(s.ID)) 
from SimulationVisit SV  
inner join Student s on s.ID = SV.StudentID  
inner join ActivityContext AC on AC.ID = SV.ActivityContextID 
where (AC.TenantID = ' + @TenantID + ' OR @TenantID is null)
  and (AC.ID =' + @ActivityContextID + ')
  and (SV.StudentID = ' + @StudentID + ')';

请帮我解决这个问题

Answer 1

不要创建串联字符串的查询，这是一种不好的做法。只写：

var stringWriter = new StringWriter(CultureInfo.InvariantCulture);
jsonOutputFormatter.WriteObject(stringWriter, value);
var responseBody = stringWriter.ToString();

Answer 2

如果动态sql是必需的，请使用参数化动态sql查询：

EXEC sp_executesql N'
SELECT COUNT(s.ID),COUNT(distinct(s.ID)) 
FROM SimulationVisit SV  
INNER JOIN Student  S ON s.ID=SV.StudentID  
INNER JOIN ActivityContext AC ON AC.ID=SV.ActivityContextID 
WHERE (AC.TenantID = @TenantID OR @TenantID is null)
AND (AC.ID = @ActivityContextID)
AND (SV.StudentID = @StudentID)',
N'  @TenantID          [SMALLINT] , 
    @ActivityContextID [INT], 
    @StudentID         [INT]',
@TenantID, @ActivityContextID, @StudentID

Answer 3

转换INT＆amp; BIGINT值为VARCHAR数据类型，格式如下：

   'SELECT count(s.ID),count(distinct(s.ID)) 
    FROM SimulationVisit SV 
    INNER JOIN Student  s on s.ID = SV.StudentID  
    INNER JOIN ActivityContext AC on AC.ID = SV.ActivityContextID 
    WHERE (AC.TenantID = '+ CAST( @TenantID AS VARCHAR ) + ' OR 
            @TenantID is null) AND 
          (AC.ID =' + CAST ( @ActivityContextID AS VARCHAR ) + ')
          AND (SV.StudentID = '+ CAST( @StudentID AS VARCHAR ) +')'

Answer 4

更新您的查询，如下所示，您必须将变量转换为字符串/ varchar值以执行动态查询

message

Answer 5

由于这是动态sql，最终的sql语句需要是varchar。相应地转换输入参数

  'select count(s.ID),count(distinct(s.ID)) from SimulationVisit SV  inner join Student  s on s.ID=SV.StudentID  
                        inner join ActivityContext AC on  AC.ID=SV.ActivityContextID 
                            WHERE (AC.TenantID = '+Cast(@TenantID as varchar(50))+' OR '+Cast(@TenantID as varchar(50))+' is null)
                             AND (AC.ID =' +Cast(@ActivityContextID as varchar(50))+')
                             AND (SV.StudentID = '+Cast(@StudentID as varchar(50))+')'

创建动态SQL查询的问题

5 个答案: