c# - 如何在 C# 中的 SQL 查询中包含变量

Question

我在 C# 代码中添加多行 SQL 代码，如下所示:

sqlCode = @"SELECT
    w.objectID,
    w.attr1397 'LastName',
    w.attr1395 'FirstName', 
    w.attr1396 'MiddleName', 
    w.attr1404 'Gender',     
    w.attr1436 'OtherName', 
    convert(varchar,w.attr1402, 101) 'DOB' ,
    w.attr1401 'SSN',   
    d.employmentStatus
FROM [db].[table] w left outer join  
     (
        WHERE w.attr1397 = '" + k + "'
        AND
        w.attr1395 = c
        AND
        w.attr1401 = s
ORDER BY 4, 2, 3";

k , c ，和s是我想要使用的函数中的变量，这就是发生的情况:

如何解决？

Answer 1

您应该使用参数化查询作为第一步，以使您的代码安全可靠。
但你的错误是由 @char 前缀的逐字字符串中断引起的

sqlCode = @"SELECT
    w.objectID,
    w.attr1397 'LastName',
    w.attr1395 'FirstName', 
    w.attr1396 'MiddleName', 
    w.attr1404 'Gender',     
    w.attr1436 'OtherName', 
    convert(varchar,w.attr1402, 101) 'DOB' ,
    w.attr1401 'SSN',   
    d.employmentStatus
FROM [db].[table] w left outer join  
     (
        WHERE w.attr1397 = '" + k + "'" + 
        " AND w.attr1395 = " + c +
        " AND w.attr1401 = " + s +
" ORDER BY 4, 2, 3";

正如我所说，建议使用参数而不是字符串连接

sqlCode = @"SELECT
    w.objectID, 
    w.attr1397 'LastName',
    w.attr1395 'FirstName', 
    w.attr1396 'MiddleName', 
    w.attr1404 'Gender',     
    w.attr1436 'OtherName', 
    convert(varchar,w.attr1402, 101) 'DOB' ,
    w.attr1401 'SSN',   
    d.employmentStatus
FROM [db].[table] w left outer join  
     (
        WHERE w.attr1397 = @k 
        AND w.attr1395 = @c
        AND w.attr1401 = @s
ORDER BY 4, 2, 3";

SqlCommand cmd = new SqlCommand(sqlCode, connection);
cmd.Parameters.AddWithValue("@k", k);
.....