SQL Script

select 10/0;

select * from sys.messages;

select * from sys.messages
where language_id = 1033;

select * from sys.messages
where language_id = 1032;

select    min(message_id) as min_message_id,
        max(message_id) as max_message_id
from sys.messages;

/*
RAISERROR ( { msg_id | msg_str | @local_variable }  
            { ,severity ,state }  
            [ ,argument [ ,...n ] ] ) [ WITH option [ ,...n ] 
*/

raiserror (9002,17,1);

raiserror ('this is error',17,1)

/*
sp_addmessage [ @msgnum= ] msg_id , [ @severity= ] severity , [ @msgtext= ] 'msg'   
     [ , [ @lang= ] 'language' ]   
     [ , [ @with_log= ] { 'TRUE' | 'FALSE' } ]   
     [ , [ @replace= ] 'replace' ]
*/

exec sp_addmessage 50001,17,N'This is my error';

raiserror (50001,17,1);
raiserror (50001,10,1);

exec sp_cycle_errorlog;

raiserror (50001,17,1) with log;
exec xp_readerrorlog 0,1;

raiserror (50001,10,1) with log;
raiserror ('hello this is my error!!',10,1) with log;
exec xp_readerrorlog 0,1;

/*
THROW [ { error_number | @local_variable },  
        { message | @local_variable },  
        { state | @local_variable } ]   
*/

throw 9002,'log full',1;

throw 50002,'my error',1;

-- state
throw 50002,'my error',1;
throw 50002,'my error',2;


create or alter proc pDemoError @num1 int , @num2 int
as
begin

    declare @num3 int = 0;
    declare @erstate int = 0;

    if ( @num1 = @num2 )
    begin
        --raiserror ('Numbers are equal',10,1);
        --select 0;
        set @erstate=1;
        throw 60000,'Numbers are equal',@erstate;
        return -1;
    end

    begin try
        set @erstate=2;
        set @num3 = @num1 / @num2;
        select @num3;
    end try
    begin catch
        declare @err_number int = ERROR_NUMBER(), 
                @err_msg nvarchar(1024) = ERROR_MESSAGE(),
                @err_severity int = ERROR_SEVERITY(),
                @err_state int = ERROR_STATE(),
                @err_line int = ERROR_LINE();
        --raiserror (@err_msg,@err_severity,@err_state);
        --raiserror (@err_msg,17,@erstate);
        --throw @err_number,@err_msg,@err_state;
        --throw 60000,@err_msg,@err_state;
        throw 60000,@err_msg,@erstate;
    end catch

end
go


exec pDemoError @num1=10 , @num2 = 10

C# Code

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;


namespace SQLErrorsTrapping
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void buttonExecute_Click(object sender, EventArgs e)
        {
            try
            {
                using (SqlConnection cn = new SqlConnection("server=sql2019;database=tempdb;trusted_connection=true;"))
                {
                    try
                    {
                        SqlCommand cmd = cn.CreateCommand();
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.CommandText = "pDemoError";
                        cmd.Parameters.AddWithValue("@num1", Convert.ToInt32(textBoxNum1.Text));
                        cmd.Parameters.AddWithValue("@num2", Convert.ToInt32(textBoxNum2.Text));
                        cn.Open();
                        MessageBox.Show(cmd.ExecuteScalar().ToString());
                    }
                    catch (SqlException sqlex)
                    {
                        StringBuilder err = new StringBuilder();

                        err.AppendFormat("Error Code\t: {0}\n", sqlex.ErrorCode.ToString());
                        err.AppendFormat("Error Number\t: {0}\n", sqlex.Number.ToString());
                        err.AppendFormat("Error Message\t: {0}\n", sqlex.Message);
                        err.AppendFormat("Error Severity\t: {0}\n", sqlex.Class.ToString());
                        err.AppendFormat("Error State\t: {0}\n", sqlex.State.ToString());

                        MessageBox.Show(err.ToString(),"SQL Server Error");
                    }
                    finally
                    {
                        if (cn.State != ConnectionState.Open) cn.Close();
                        cn.Dispose();
                    }
                    
                }
            }
            
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            
        }
    }
}