C# 如果在 SQL 更新中可用，否则插入

Question

I have checked many posts on Stackoverflow but I am still stuck with the query below. I am a beginner learning C# and would request help.

Error: Incorrect Syntax near keyword ELSE

I am trying to check if the Question1 or Question2 if either of them is selected the below should be executed. Also other time it gave me an error @answer2 not defined.

string query = @"IF EXISTS(SELECT * FROM dbo.tbl_pkt_Answers_Submitted  WHERE (Questions = @Question1 or Questions = @Question2))

    UPDATE dbo.tbl_pkt_Answers_Submitted 
    SET AnswersSubmitted = @Answer1
    WHERE Questions = @Question1;

    UPDATE dbo.tbl_pkt_Answers_Submitted 
    SET AnswersSubmitted = @Answer2
    WHERE Questions = @Question2;

    ELSE

    INSERT INTO dbo.tbl_pkt_Answers_Submitted(Questions, AnswersSubmitted)   
    VALUES (@Question1, @Answer1), (@Question2, @Answer2);";

SqlCommand cmd = new SqlCommand(query, con);

cmd.Parameters.Add("@Question1", lblQuestion1.Text);
cmd.Parameters.Add("@Question2", lblQuestion2.Text);

if (rdq1a1.Checked)
{
    cmd.Parameters.Add("@Answer1", rdq1a1.Text);
}

if (rdq1a2.Checked)
{
    cmd.Parameters.Add("@Answer1", rdq1a2.Text);
}

if (rdq1a3.Checked)
{
    cmd.Parameters.Add("@Answer1", rdq1a3.Text);
}

if (rdq1a4.Checked)
{
    cmd.Parameters.Add("@Answer1", rdq1a4.Text);
}

if (rdq2a1.Checked)
{
    cmd.Parameters.Add("@Answer2", rdq2a1.Text);
}

if (rdq2a2.Checked)
{
    cmd.Parameters.Add("@Answer2", rdq2a2.Text);
}

if (rdq2a3.Checked)
{
    cmd.Parameters.Add("@Answer2", rdq2a3.Text);
}

if (rdq2a4.Checked)
{
    cmd.Parameters.Add("@Answer2", rdq2a4.Text);
}

con.Open();
cmd.ExecuteNonQuery();

MessageBox.Show("Your Data has been saved");
con.Close();

Answer 1

The 'true' part of the IF statement contains multiple SQL statements, you must surround these statements within BEGIN and END

string query = @"IF EXISTS(SELECT * FROM dbo.tbl_pkt_Answers_Submitted  WHERE (Questions = @Question1 or Questions = @Question2))
                 BEGIN
                    UPDATE dbo.tbl_pkt_Answers_Submitted 
                    SET AnswersSubmitted = @Answer1
                    WHERE Questions = @Question1;

                    UPDATE dbo.tbl_pkt_Answers_Submitted 
                    SET AnswersSubmitted = @Answer2
                    WHERE Questions = @Question2;
                 END
                 ELSE
                    INSERT INTO dbo.tbl_pkt_Answers_Submitted(Questions, AnswersSubmitted) 
                    VALUES(@Question1, @Answer1), (@Question2, @Answer2);";

Answer 2

The main problem here is that your UPDATE statements after the IF are not enclosed with BEGIN and END . Not using those only works with single batch statements, not multiple. So your statement should look like:

IF EXISTS(..)
BEGIN
UPDATE 1
UPDATE 2
END
ELSE
yadayada

Answer 3

It appears that your Insert statement looks suspicious.

INSERT INTO dbo.tbl_pkt_Answers_Submitted(Questions, AnswersSubmitted) 
VALUES(@Question1, @Answer1)";

also, it isnt surrounded by begin and end statement. It should be

If exists ...
begin
...
end
else 
insert

Answer 4

You have multiple statements in your if condition being true. If there is one statement then it is okay, but with multiple statements, you need to use BEGIN...END

IF EXISTS(SELECT *
          FROM dbo.tbl_pkt_Answers_Submitted
          WHERE (Questions = @Question1 OR Questions = @Question2))
    BEGIN
        UPDATE dbo.tbl_pkt_Answers_Submitted
        SET AnswersSubmitted = @Answer1
        WHERE Questions = @Question1;

        UPDATE dbo.tbl_pkt_Answers_Submitted
        SET AnswersSubmitted = @Answer2
        WHERE Questions = @Question2;
    END
ELSE
    INSERT INTO dbo.tbl_pkt_Answers_Submitted(Questions, AnswersSubmitted)
    VALUES (@Question1, @Answer1),
           (@Question2, @Answer2);