MySQL Insert语句中的where条件

Question

Can I use where condition in Insert statement???? I have coded like this, its showng me an error call MySQLException was unhandled, You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE RegistrationID='3'' at line 1. My code:-

MySqlCommand cmd1 = new MySqlCommand("INSERT INTO registration(DueAmount) VALUES ('"+textBox5.Text + "') WHERE RegistrationID='"+textBox2.Text+"'",connection);

Answer 1

The correct syntax of INSERT doesn't have WHERE clause. I think you want UPDATE instead of INSERT ,

UPDATE registration 
SET DueAmount = 'txt5'
WHERE RegistrationID = 'txt2'

the only way you can use WHERE in SELECT is when you are using INSERT INTO....SELECT statement.

one more thing, since you are using ADO.NET , make sure that you parameterized your query to avoid SQL Injection , and use USING statement.

string query = "UPDATE  registration 
                SET     DueAmount = @dateAmount
                WHERE   RegistrationID = @RegID"
using (MySqlCommand cmd1 = new MySqlCommand(query,connection))
{
    cmd1.CommandType = CommandType.Text;
    cmd.Parameters.AddWithValue("@dateAmount", textBox5.Text);
    cmd.Parameters.AddWithValue("@RegID", textBox2.Text);

    // other codes
}

Answer 2

You're mixing 2 different statements.

• An UPDATE statement updates an existing row in your table.
• An INSERT statement adds a new row in your table.

I think you want to use an UPDATE statement and modify an existing row.

MySqlCommand cmd1 = new MySqlCommand("
UPDATE Registration Set DueAmount= '"+textBox5.Text 
+ "' WHERE RegistrationID='"+textBox2.Text+"'",connection);

Answer 3

INSERT with WHERE doesn't make sense. INSERT always inserts a new row. You might be looking for REPLACE INTO which does a insert if that record doesnt exist or an update if it does based on its primary key.

Answer 4

INSERT puts a new line to database. You can not put a new line WHERE sth is sth. But you can UPDATE it. Hope this helps.

Answer 5

You need to use an UPDATE statement.

tHS SYNTAX IS SIMILAR: "UPDATE registration SET DueAmount = '" + textBox5.Text + "' WHERE RegistrationID='"+textBox2.Text+"'"

Answer 6

You can try with Update

var query = "UPDATE Registration SET DueAmount= $Paremeter1 WHERE RegistrationID = $Paremeter2";
var cmd1 = new MySqlCommand(query, connection);

cmd1 .Parameters.AddWithValue("$Paremeter1", textBox5.Text);
cmd1 .Parameters.AddWithValue("$Paremeter2", textBox2.Text);