我在尝试修改SQL查询以解决有关潜在SQL注入的警告时遇到了一个问题。我打算对查询进行参数化并使用原始字符串文字，但我收到了一条错误消息。
这个错误似乎与我的列名的大小写敏感性有关，不幸的是，我不能改变整个数据库来删除它们。
我已经尝试了各种其他方法，但它们要么导致错误，要么无法正确检索UserId。
下面是我试过的代码。
1.原始版本（SQL注入问题）

await dbContext.Database.ExecuteSqlRawAsync(
$@"
    DO $$ 
    BEGIN 
        IF (SELECT COUNT(*) FROM ""Notification"" WHERE ""UserId"" = '{userId}') > 20 THEN
            DELETE FROM ""Notification""
            WHERE ""UserId"" = '{userId}' AND ""IsReceived"" = 'TRUE' AND ""ContentId"" NOT IN (
                SELECT ""ContentId"" FROM ""Notification""
                WHERE ""UserId"" = '{userId}'
                ORDER BY ""CreatedAt"" DESC
                LIMIT 20
            );
        END IF;
    END $$"
);

字符串
1.原始字符串文字版本
（错误：Npgsql.PostgresException：42703：列“userid”不存在）

var param = new NpgsqlParameter("@UserId", userId);
await dbContext.Database.ExecuteSqlRawAsync(
"""
    DO $$ 
    BEGIN 
        IF (SELECT COUNT(*) FROM "Notification" WHERE "UserId" = @UserId) > 20 THEN
            DELETE FROM "Notification"
            WHERE "UserId" = @UserId AND "IsReceived" = 'TRUE' AND "ContentId" NOT IN (
                SELECT "ContentId" FROM "Notification"
                WHERE "UserId" = @UserId
                ORDER BY "CreatedAt" DESC
                LIMIT 20
            );
        END IF;
    END $$
""", param);

型
1.带有ExecuteSqlInterpolatedAsync的原始字符串文本版本
（错误：Npgsql.PostgresException：42703：列“p0”不存在）

await dbContext.Database.ExecuteSqlInterpolatedAsync(
$"""
    DO $$ 
    BEGIN 
        IF (SELECT COUNT(*) FROM "Notification" WHERE "UserId" = {userId}) > 20 THEN
            DELETE FROM "Notification"
            WHERE "UserId" = {userId} AND "IsReceived" = 'TRUE' AND "ContentId" NOT IN (
                SELECT "ContentId" FROM "Notification"
                WHERE "UserId" = {userId}
                ORDER BY "CreatedAt" DESC
                LIMIT 20
            );
        END IF;
    END $$
""");

型
我希望你能告诉我如何进行修改。
感谢您的帮助！