SQL/C# - UPSERT 上的主键错误

UPDATE（简化的问题，从问题中删除了 C#）

在以下情况下，如何编写一个可以识别两行相同的 UPSERT...

看看怎么有一个\b [退格键]在那里编码（奇怪的小字符）？ SQL 将它们视为相同。虽然我的 UPSERT 将此视为new data并在应该有更新的地方尝试插入。

//UPSERT
    INSERT INTO [table]
    SELECT [col1] = @col1, [col2] = @col2, [col3] = @col3, [col4] = @col4
    FROM [table]
    WHERE NOT EXISTS
       -- race condition risk here?
       ( SELECT 1 FROM [table] 
       WHERE 
            [col1] = @col1 
        AND [col2] = @col2
        AND [col3] = @col3)

    UPDATE [table]
        SET [col4] = @col4
        WHERE 
        [col1] = @col1 
        AND [col2] = @col2
        AND [col3] = @col3

您需要 @ 符号，否则会遇到 C# 字符转义序列。

C# 定义了以下字符转义序列：

\' - single quote, needed for character literals 
\" - double quote, needed for string literals 
\\ - backslash 
\0 - Unicode character 0 
\a - Alert (character 7) 
\b - Backspace (character 8) 
\f - Form feed (character 12) 
\n - New line (character 10) 
\r - Carriage return (character 13) 
\t - Horizontal tab (character 9) 
\v - Vertical quote (character 11) 
\uxxxx - Unicode escape sequence for character with hex value xxxx 
\xn[n][n][n] - Unicode escape sequence for character with hex value nnnn (variable length version of \uxxxx) 
\Uxxxxxxxx - Unicode escape sequence for character with hex value xxxxxxxx (for generating surrogates)