如何从表中选择具有所有字段值的记录

Question

frmAdd f = new frmAdd(); string connectionString = ("Server=(localdb)\\v11.0;AttachDbFileName=" + Application.StartupPath + "\\Database\\" + f.databaseName + ".mdf;Connect Timeout=30;"); SqlConnection connection = new SqlConnection(connectionString);

        //notes=error, id and group=no like
        string selectCommand = "SELECT * FROM ContactsList WHERE " +
                "NamePrefix LIKE @prefix AND GivenName LIKE @given AND MiddleName LIKE @middle AND FamilyName LIKE @family AND " +
                "NameSuffix LIKE @suffix AND NickName LIKE @nick AND Company LIKE @company AND JobTitle LIKE @job AND " +
                "MobilePhone LIKE @mobilep AND HomePhone LIKE @homep AND WorkPhone LIKE @workp AND WorkFaxPhone LIKE @workfp AND HomeFaxPhone LIKE @homefp AND " +
                "PagerPhone LIKE @pagerp AND CallBackPhone LIKE @callbp AND OtherPhone LIKE @otherp AND GroupName=@group AND Relationship LIKE @relation AND " +
                "StreetHome LIKE @strh AND CityHome LIKE @cityh AND StateHome LIKE @stah AND ZipCodeHome LIKE @ziph AND CountryHome LIKE @countryh AND " +
                "StreetWork LIKE @strw AND CityWork LIKE @cityw AND StateWork LIKE @staw AND ZipCodeWork LIKE @zipw AND CountryWork LIKE @countryw AND " +
                "StreetOther LIKE @stro AND CityOther LIKE @cityo AND StateOther LIKE @stao AND ZipCodeOther LIKE @zipo AND CountryOther LIKE @countryo AND " +
                "HomeMail LIKE @homem AND WorkMail LIKE @workm AND OtherMail LIKE @otherm AND Website1 LIKE @web1 AND Website2 LIKE @web2 AND Website3 LIKE @web3 AND " +
                "Facebook LIKE @face AND GooglePlus LIKE @google AND BirthdayEvent LIKE @birth AND AnniversaryEvent LIKE @anni AND OtherEvent LIKE @othere";

        SqlCommand command1 = new SqlCommand(selectCommand);
        command1.Connection = connection;
        command1.CommandType = CommandType.Text;

        //if (!string.IsNullOrWhiteSpace(txtId.Text))
        //{
        //    command1.Parameters.AddWithValue("@id", txtId.Text);
        //}
        //else
        //{
        //    command1.Parameters.AddWithValue("@id", "%%");
        //}

        if (!string.IsNullOrWhiteSpace(txtPrefix.Text))
        {
            command1.Parameters.AddWithValue("@prefix", "%" + txtPrefix.Text + "%");
        }
        else
        {
            command1.Parameters.AddWithValue("@prefix", "%%");
        }

        if (!string.IsNullOrWhiteSpace(txtGiven.Text))
        {
            command1.Parameters.AddWithValue("@given", "%" + txtGiven.Text + "%");
        }
        else
        {
            command1.Parameters.AddWithValue("@given", "%%");
        }

. . . . . .. .. . . and so on

Answer 1

SqlCommand command1 = new SqlCommand("SELECT * FROM ContactsList WHERE ID LIKE @id");

Answer 2

Another way:

     SqlCommand command1 = null;

    if (!string.IsNullOrWhiteSpace(txtId.Text))
    {
       command1 = new SqlCommand("SELECT * FROM ContactsList WHERE ID = @id");
       command1.Parameters.AddWithValue("@id", txtId.Text);
    }
    else
    {
       command1 = new SqlCommand("SELECT * FROM ContactsList ");
    }

    command1.Connection = connection;
    command1.CommandType = CommandType.Text;

Answer 3

try this : It depends on Data-Type of your Column["code"] of Table["server"].

If Data-Type is Int/Numeric, then below code should work.

cmd.CommandText = "SELECT name FROM server WHERE code="+TextBox1.Text;

In case Data-Type is Varchar / Non-Numeric then try as below.

cmd.CommandText = "SELECT name FROM server WHERE code='" + TextBox1.Text + "'";

However, I don't recommend in-line queries to you. Instead use parametrized query. Because plain inline query is an invite for SQL-Injection.

string sqlConnectString = "YourConnectionString";
string sqlSelect = "SELECT name FROM server WHERE code= @CodeValue";

SqlConnection sqlConnection = new SqlConnection(sqlConnectString);
SqlCommand sqlCommand = new SqlCommand(sqlSelect, sqlConnection);

sqlCommand.Parameters.Add("@CodeValue", System.Data.SqlDbType.Int);// Set SqlDbType based on your DB column Data-Type

 sqlCommand.Parameters["@CodeValue"].Value = TextBox1.Text;

SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCommand);
DataTable sqlDt = new DataTable();
sqlDa.Fill(sqlDt);

this is a short tuto to help