如何修复代码中的 SqlException 不正确的语法错误？

Question

This is code that references a SQL Server database to retrieve to information to be put into a DataGridView .

I get an error:

SqlException [incorrect syntax]

Code:

private void DisplayData()
{
    adapt = new SqlDataAdapter("SELECT geoCode, cancer2004" +
                               "FROM Regional_Intel$" +
                               "WHERE geoCode LIKE '" + txtDMA.Text + "'", con);
    // cmd.Parameters.AddWithValue("@dma", txtDMA.Text);

    dt = new DataTable();
    adapt.Fill(dt);

    dataGridView1.DataSource = dt;
}

How can I fix it?

Answer 1

Add spaces in your SQL string. Also, very bad idea to use string concatenation.

Add spaces like this:

{
    adapt = new SqlDataAdapter("Select geoCode, cancer2004 " +
        "FROM Regional_Intel$ " +
        "where geoCode LIKE '" + txtDMA.Text + "'", con);
    //cmd.Parameters.AddWithValue("@dma", txtDMA.Text);
    dt = new DataTable();
    adapt.Fill(dt);
    dataGridView1.DataSource = dt;
}

Use parameters like this:

{
    adapt = new SqlDataAdapter("Select geoCode, cancer2004 " +
        "FROM Regional_Intel$ " +
        "where geoCode LIKE @dma", con);
    adapt.SelectCommand.Parameters.Add("@dma", SqlDbType.NVarChar).Value = txtDMA.Text;
    dt = new DataTable();
    adapt.Fill(dt);
    dataGridView1.DataSource = dt;
}

Separate out your SQL string:

{
   var query = @"
SELECT geoCode, cancer2004
FROM Regional_Intel$
WHERE geoCode LIKE @dma";
    adapt = new SqlDataAdapter(query, con);
    adapt.SelectCommand.Parameters.Add("@dma", SqlDbType.NVarChar).Value = txtDMA.Text;
    dt = new DataTable();
    adapt.Fill(dt);
    dataGridView1.DataSource = dt;
}