将 varchar 转换为数据类型 int 时转换失败：SQL

Question

我正在 asp.net mvc 中创建一个网络应用我有一个如下所示的查询

using (SqlConnection conn = new SqlConnection(_connStr))
{
    conn.Open();

    var p = new DynamicParameters();
    p.Add("@SP_RoleId", "7,8,9", dbType: DbType.String, direction: ParameterDirection.Input);
    p.Add("@SP_UserId", userId, dbType: DbType.Int32, direction: ParameterDirection.Input);

    var obj = conn.Query<PendingKmsRequest>(sql: "SELECT [f].[id] AS [FileId],[fvr].[Id] AS [RequestId], [au].[Name]"
                        + ", [fvr].[RequestByUserId], [fvr].[FromDate], [fvr].[ToDate],[f].[Title], [fvr].[Status], [fvr].[StatusRemarks]"
                        + "FROM [dbo].[File] AS[f]"
                        + "INNER JOIN [dbo].[FileViewRequest] AS [fvr] ON [f].[CurrentFileVersionId] = [fvr].[FileVersionId]"
                        + "INNER JOIN [Access].[User] AS [au] ON [fvr].[RequestByUserId] = [au].[Id]"
                        + "WHERE ([fvr].[Status] = 'P' OR ([fvr].[Status] = 'A' AND [fvr].[StatusByUserId] = @SP_UserId AND GETDATE() BETWEEN [fvr].[FromDate] AND [fvr].[ToDate]))"
                        + "AND (SELECT 1 FROM [Access].[UserRoleMap] WHERE UserId=@SP_UserId AND RoleId IN(@SP_RoleId)) = 1", param: p, commandType: CommandType.Text);

    if (obj != null && obj.Count() > 0)
        return obj.ToList();
    else
        return new List<PendingKmsRequest>();
}

注意：角色 ID 总是类似于 (7,8,9)，它是数据库中的 int 列。

我在这行代码中遇到此转换错误：

 WHERE UserId = @SP_UserId AND RoleId IN (@SP_RoleId))

这是错误：

Conversion failed when converting the nvarchar value '7,9,10' to data type int.

我怎样才能避免这个错误？

Answer 1

您的问题代码中的以下行：

p.Add("@SP_RoleId", "7,8,9", dbType: DbType.String, direction: ParameterDirection.Input);

值"7,8,9"为字符串，参数类型DbType.String也为字符串

但是，你说这是你数据库中的 int。这是不匹配。

此外，您的查询：

WHERE UserId = @SP_UserId AND RoleId IN (@SP_RoleId))

查询正在使用 IN 子句。

如果传入 IEnumerable.

，Dapper 可以转换 IN 子句的值

更改代码行如下：

p.Add("@SP_RoleId", new[] {7,8,9}, dbType: DbType.Int32, direction: ParameterDirection.Input);

Answer 2

无需在 array 或任何字符串 split() 函数中使用转换字符串

如果你有逗号分隔的字符串，那么你可以按照下面的步骤检查它，

如果你有@SP_RoleId = "7, 8, 9"
您可以按如下方式转换此字符串
@SP_RoleId = ",7,8,9," ( ',' + ltrim(rtrim( @SP_RoleId )) + ',' )
现在使用Like检查,UserId,

更新代码如下,

using (SqlConnection conn = new SqlConnection(_connStr))
{
    conn.Open();

    var p = new DynamicParameters();
    p.Add("@SP_RoleId", "7,8,9", dbType: DbType.String, direction: ParameterDirection.Input);
    p.Add("@SP_UserId", userId, dbType: DbType.Int32, direction: ParameterDirection.Input);

    var obj = conn.Query<PendingKmsRequest>(sql: "SELECT [f].[id] AS [FileId],[fvr].[Id] AS [RequestId], [au].[Name]"
                        + ", [fvr].[RequestByUserId], [fvr].[FromDate], [fvr].[ToDate],[f].[Title], [fvr].[Status], [fvr].[StatusRemarks]"
                        + "FROM [dbo].[File] AS[f]"
                        + "INNER JOIN [dbo].[FileViewRequest] AS [fvr] ON [f].[CurrentFileVersionId] = [fvr].[FileVersionId]"
                        + "INNER JOIN [Access].[User] AS [au] ON [fvr].[RequestByUserId] = [au].[Id]"
                        + "WHERE ([fvr].[Status] = 'P' OR ([fvr].[Status] = 'A' AND [fvr].[StatusByUserId] = @SP_UserId AND GETDATE() BETWEEN [fvr].[FromDate] AND [fvr].[ToDate]))"
                        + "AND (SELECT 1 FROM [Access].[UserRoleMap] WHERE ',' +  lTrim(rTrim(@SP_RoleId)) + ',' like '%,' + lTrim(rTrim(UserId) + ',%' " // Updated line
                        + "AND RoleId IN(@SP_RoleId)) = 1", param: p, commandType: CommandType.Text);

    if (obj != null && obj.Count() > 0)
        return obj.ToList();
    else
        return new List<PendingKmsRequest>();
}

将 varchar 转换为数据类型 int 时转换失败：SQL

Conversion failed when converting the varchar to data type int: SQL

asp.net

sql-server

dapper

dynamicparameters