Develop Reference

Trying to get the value of a SQL query into a string

I am running a SQL query on SQL Server inside of my WPF C# application. The query returns a string which contains the value called MYCOUNT that I want to return to GetNumber. How do I return the value MYCOUNT only to get number and not the entire string?
public string GetNumber(string SkillNumber)
{
DateTime dte = DateTime.Today;
string fixedStartDate = String.Format("{0:yyyy-MM-dd " + "05:00:00.000" + "}", dte);
string fixedEndDate = String.Format("{0:yyyy-MM-dd " + "05:00:00.000" + "}", dte.AddDays(1));
using (IDbConnection connection = new System.Data.SqlClient.SqlConnection(SQLHelper.CnnCal("OADB")))
{
var x = connection.Query($"SELECT COUNT(SOURCEID) AS 'MYCOUNT' "
+ "FROM [OADB].[oadb].[CmsCallHistory] "
+ "WHERE disposition = 2 and DISPSPLIT in (" + SkillNumber + ") AND SEGSTOP BETWEEN '" +
fixedStartDate + "' and '" + fixedEndDate + "'");
return x.ToString();
}
}
This is what returns. I only need to return the value:

You get an error because the Dapper Query method returns an IEnumerable, not a single value (indeed you can see that you have one object (an int) in the IEnumerable returned and this object has the value '767')
In Dapper you can use ExecuteScalar to get a single scalar value as your query returns
var x = connection.ExecuteScalar<int>(.....)
You can also still use the Query method but with a Linq twist
var x = connection.Query(.....).Single();
The usual warning about Sql Injection applies to your code albeit parameterize an IN clause is not so simple. And the two dates should be definitively parameters to avoid parsing incompatibilities between what you consider to be a date and what instead the sql server and its locale thinks about transforming a string to a datetime.

Your answer is in the msdn documentation:
https://msdn.microsoft.com/en-us/library/system.data.idbconnection(v=vs.110).aspx
You can try using
using (IDbConnection connection = new System.Data.SqlClient.SqlConnection(SQLHelper.CnnCal("OADB")))
{
IDbCommand command = connection.createCommand();
command.CommandText = $"SELECT COUNT(SOURCEID) AS 'MYCOUNT' "
+ "FROM [OADB].[oadb].[CmsCallHistory] "
+ "WHERE disposition = 2 and DISPSPLIT in (" + SkillNumber + ") AND SEGSTOP BETWEEN '" +
fixedStartDate + "' and '" + fixedEndDate + "'";
return (string)command.ExecuteScalar();
}
Another note: You want to try and close the connection once you are done. I recommend putting this in a try/catch/finally statement so you can close your connection in the 'finally' section.
Hope this helps!

Issues with the update query SQL

am writing a c# code in which am trying to update 4 of the 10 columns of the table. Here is my function type in which am sending arguments for the query:
public int checkout_visitor(int check_inn, int checkout, String time_out, String date_out, String cnic)
Now what happens is that i call this function somewhere in my program providing values in argument:
checkout_visitor(chk_in,chk_out,t_out,dt_out,idcardnum);
The query am using to update my columns is given by:
String query2 = " UPDATE visit_detail SET[check_in] = " + check_inn + "[check_out] = " + checkout + "[time_out] = " + time_out + "[date_out] =" + date_out + "where visit_detail.v_id = "+ v_idd;
Given me exception incorrect syntax near chkout. Where am i wrong?? is the syntax correct? how do i correct it?
code:
public int checkout_visitor(int check_inn, int checkout, String time_out, String date_out, String cnic)
{
try
{
connection.Open();
String query = "select v_id from visitor where visitor.cnic=" + cnic;
command = connection.CreateCommand();
command.CommandText = query;
visitor_id = command.ExecuteScalar().ToString();
int v_idd = Int32.Parse(visitor_id);
String query2 = " UPDATE visit_detail SET[check_in] = " + check_inn + "[check_out] = " + checkout + "[time_out] = " + time_out + "[date_out] =" + date_out + "where visit_detail.v_id = " + v_idd;
//String query2 = "UPDATE visit_detail SET [check_in] = " + check_inn + ",[check_out] = " + checkout + ",[time_out] = " + time_out + ",[date_out] =" + date_out + " where visit_detail.v_id = " + v_idd;
command = connection.CreateCommand();
command.CommandText = query2;
int result = command.ExecuteNonQuery();
connection.Close();
return result;
}
catch (Exception e)
{
return -1;
}
}

Problem :
1.you are not seperating the Parameters properly using comma , .
2.you are not giving the sapace between SET and check_in parameter.
Try This:
String query2 = "UPDATE visit_detail SET [check_in] = " + check_inn + ",[check_out] = " + checkout + ",[time_out] = '" + time_out + "',[date_out] ='" + date_out + "' where visit_detail.v_id = "+ v_idd;

Do you see the resulting query? It seems to me you're missing some comma, but you should print (and post) the resulting query to have a better understanding of the issue.

You are missing ',' between the column names.
Its like Update Table Set col1=3,col2='test'

The problem is that query2 string will be something along the lines:
UPDATE visit_detail SET[check_in] = " 1[check_out] = 2[time_out] = some time[date_out] =some datewhere visit_detail.v_id = 5
So you can already see that there's datewhere that is incorect, there are also no ' characters around string parameters, and no commas between parameters.
Quick fix to that would be:
String query2 = String.Format("UPDATE visit_detail SET [check_in]={0}, [check_out]={1}, [time_out]='{2}', [date_out]='{3}' where visit_detail.v_id={4};", check_inn, checkout, time_out, date_out, v_idd);
But this is still not valid. If time_out contains ' characters, you'll again receive an error.
What you should really use is this:
SqlCommand.Parameters
This is a proper way of passing paramters to your command, all the problems will be taken care of for you.

Is there a LIKE operator that will include NULL values?

I'm using SQL Server 2008, with a C# front end. I'm trying to pass a SQL string from C# to SQL Server, and there are 2 fields in my WHERE statement that sometimes might contain NULL values. I've got this code on my Page Load in the code-behind (this is for a report that will be placed in a datagrid):
protected void Page_Load(object sender, EventArgs e)
{
SqlConnection sqlconnectionStatus = new SqlConnection(str);
string DDL_Value = Convert.ToString(Request.QueryString["DDL_Val"]);
string Val_Value = Convert.ToString(Request.QueryString["Val_Val"]);
string Trk_Value = Convert.ToString(Request.QueryString["Trk_Val"]);
string StDt_Value = Convert.ToString(Request.QueryString["StDt_Val"]);
string EnDt_Value = Convert.ToString(Request.QueryString["EnDt_Val"]);
string BTN_Value;
// Because the date is stored as an INT, you have to request the string and then
// convert it to an INT
string StDT_Vals = Request.QueryString["StDt_Val"].ToString();
string EnDT_Vals = Request.QueryString["EnDt_Val"].ToString();
string sqlquery;
sqlquery = "Select DISTINCT PL.PROC_NM as Agent_Name, CCM.UNIQUE_CLAIM_ID as Unique_ID, CCM.CLAIM_ID as Claim_Number, ";
sqlquery = sqlquery + "CCM.SOCSEC as Employee_Last_Digit, CCM.DATE_IMPORTED as Import_Date, CCM.Orig_Open_Date as Original_Review_Date, ";
sqlquery = sqlquery + "AGL.ACCT_GRP as Account_Name, AL.ACCT_NUM as Account_Number, CCM.CDBBEN as Benefit_Option, CCM.BENEFIT_TYPE1 as Benefit_Type1, ";
sqlquery = sqlquery + "CCM.BENEFIT_TYPE2 as Benefit_Type2, CCM.BENEFIT_TYPE3 as Benefit_Type3, CCM.Cmplt as Review_Validated, CCM.Vldtn_Cmmnts as Validation_Comments, ";
sqlquery = sqlquery + "CCM.Gtkpr_Cmmnts as Gatekeeper_Comments, TS.StatusText as Tracking_Status ";
sqlquery = sqlquery + "from ClosedClaims_MERGE CCM ";
sqlquery = sqlquery + "LEFT JOIN PROC_LIST PL ON CCM.Spare = PL.LOGIN ";
sqlquery = sqlquery + "LEFT JOIN ACCT_LIST AL ON AL.ACCT_NUM = CCM.CDBACC ";
sqlquery = sqlquery + "LEFT JOIN ACCT_GRP_LIST AGL ON AGL.ACCT_GRP_PK = AL.ACCT_GRP_FK ";
sqlquery = sqlquery + "LEFT JOIN TrackingStatus TS ON TS.StatusCode = CCM.TrackingStatus ";
sqlquery = sqlquery + "WHERE CCM.Spare LIKE '" + DDL_Value + "' AND CCM.Cmplt LIKE '" + Val_Value + "' AND CCM.TrackingStatus IN (" + Trk_Value + ") AND CCM.DATE_IMPORTED >= '" + StDt_Value + "' AND CCM.DATE_IMPORTED <= '" + EnDt_Value + "'";
}
The code is sound, it works perfectly fine if a value is selected for all report parameters. The problem is CCM.Spare and CCM.Cmplt can have specific values chosen from a dropdown, or they can be left blank. If left blank, then they need to pull ALL values, whether they're NULL or not. When I leave one (or both) blank, that's where the SQL fails.
I tried checking for blanks and setting the variable equal to '%', but that obviously isn't working; it will only pick up records where there is a value in the field.
I want to do this with one statement if possible before I go cludging it with some If/Then/Else loops.
Is this possible?

try this, I just included the code for the first criteria.
As recommended above, don't concatenate your parameters; the second option is the best way to do it:
sqlquery = sqlquery +
"WHERE CCM.Spare " + (DDL_Value == null ? "IS NULL" : "LIKE '" + DDL_Value + "'") + " AND ...";
sqlquery = sqlquery +
"WHERE CCM.Spare " + (DDL_Value == null ? "IS NULL" : "LIKE #par1") + " AND ...";
Additionaly to increase the speed of your query you could do:
sqlquery = sqlquery +
"WHERE " + (DDL_Value != null ? "CCM.Spare LIKE #par1 AND " : "") + "...";
this will ignore the whole criteria on CCM.Spare if your parameter is null.

If you want all possible values of CCM.Spare and CCM.Cmplt, you simply need to leave off the predicate. Build a separate query (preferable using parametrized queries, as marc_s points out) that omits the WHERE clause referencing the empty dropdown value.

Update/Insert into table

I have to update table on SQL Server but first i have to check for existing data in table so if data is there update it, if not make a new insert:
cmd_sql.CommandText = " SELECT BrDok as id_dok " +
" FROM ordersstavke " +
" WHERE SifParFil = '" + rw_mat["sifskl_kor"] + "'" +
" AND DokumentTip = '" + rw_mat["vrst_dok"] + "'";
MySqlDataAdapter sql_adapter = new MySqlDataAdapter(cmd_sql);
DataSet dt_dok = new DataSet("DOK_MAT_EXCHANGE");
sql_adapter.Fill(dt_dok);
if (dt_dok.Tables["DOK_MAT_EXCHANGE"].Rows.Count == 0)
{
myQuery = " INSERT INTO ordersstavke (BrDok, DocumentTip, SifParFil) " +
" VALUES ('" + rw_mat["brdok"] + "', '" +
rw_mat["vrst_dok"] + "', '" +
rw_mat["sifskl_kor"] + "')";
}
else
{
UPDATE DATA
}
But I have an error in the code, the error is here if (dt_dok.Tables["DOK_MAT_EXCHANGE"].Rows.Count == 0)
Object reference not set to an instance of an object.
The problem is in this if statement...

DOK_MAT_EXCHANGE is the name of the DataSet, not of the first table.
You should test with
if (dt_dok.Tables[0].Rows.Count == 0)
Also, I think is better to use a syntax like this to discover how many records are presents
cmd_sql.CommandText = "SELECT COUNT(BrDok) as id_dok " +
" FROM ordersstavke " +
" WHERE SifParFil = ?p1 " +
" AND DokumentTip = ?p2";
cmd_sql.Parameters.AddWithValue("?p1", rw_mat["sifskl_kor"] );
cmd_sql.Parameters.AddWithValue("?p2", rw_mat["vrst_dok"] );
int rowCount = (Int32)cmd_sql.ExecuteScalar();

change
DataSet dt_dok = new DataSet("DOK_MAT_EXCHANGE");
to
DataSet dt_dok = new DataSet("ordersstavke ");
and
if (dt_dok.Tables["DOK_MAT_EXCHANGE"].Rows.Count == 0)
to
if (dt_dok.Tables["ordersstavke "].Rows.Count == 0)

Accessing the first table via the dataset name is incorrect, that's for setting the XML.
Instead use
dt_dok.Tables[0].Rows.Count;
That being said, you're better off writing this as a single SQL statement instead of a separate select && insert. This way you're not going to the DB multiple times.
var sql = #"if exists(select * from ordersstavke where SifParFil = ? and DokumentTip = ?)
then
-- do insert statement
else
-- do update
end if";
This might also be better done with a stored proc, so you don't have as much SQL code in C#. It's easier to manage multiple operations that way.
And for crying out loud, use SqlParameters, not string concatenation! That's just asking for trouble!

Ok, thanks guys, I wrote it like this
if (ds_dok.Tables[0].Rows.Count <= 0)
{
myQuery = " INSERT INTO ordersstavke (BrDok, " +
" SifParFil) " +
" VALUES ('" + rw_mat["brdok"] + "', '" +
rw_mat["sifskl_kor"] + "')";
}
else if (ds_dok.Tables[0].Rows.Count >= 1)
{
myQuery = "UPDATE ordersstavke " +
"SET BrDok = '" + rw_mat["brdok"] + "', " +
"SifParFil = '" + rw_mat["sifskl_kor"] + "', " +
"WHERE BrDok = " + ds_dok.Tables["ordersstavke"].Rows[0]["BrDok"].ToString() + "'";
}
But there is a small problem in the section update: s_dok.Tables["ordersstavke"].Rows[0]["BrDok"].ToString(), here it give me that loving error : Object reference not set to an instance of an object.
Maybe the update on MySQL goes on different way, I'm referencing on example on sql server and there update goes differently

MySQL Returning Column Names instead of their Content

Okay, so in the past few weeks I've probably written about 40 select statements. So, I know how to do it. And I've just written another one, but this time I need to use ComboBox values to match against, and it keeps resulting in the names of the column (the right column, mind you), instead of what's inside the column.
string st = "SELECT '" + txtchange.Text + "'
FROM mysql_9269_dbase." + pages.Text + "";
MySql.Data.MySqlClient.MySqlCommand cd = new MySql.Data.MySqlClient.MySqlCommand(st, msc);
cd.CommandType = CommandType.Text;
MySql.Data.MySqlClient.MySqlDataReader msdr = cd.ExecuteReader();
while(msdr.Read())
{
txt.Text = msdr[0].ToString();
}
Now, why is it returning the column name instead of the content of that column?

Lose the single quotes.
Change
"SELECT '" + txtchange.Text + "' "
to
"SELECT " + txtchange.Text + " "

In sql you can do it like this.
string query = "Execute("+"'SELECT " + txtchange.Text + " FROM mysql_9269_dbase." + pages.Text + "')";