c# Mysql problem with where clause

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Can we use in windows c# form the "where" clause with the parameter from object in c#
for fill a datagridview
example :

SQL

SELECT         Value, IdCategory, CreateDate, Description, IdUser
FROM            profit
WHERE        (IdUser = USER)

where "USER" is variable in c#

Thank you!

Posted 1-Aug-12 9:52am

kespinko

Updated 1-Aug-12 9:55am

Kenneth Haugland

v2

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Comments

[no name] 1-Aug-12 15:57pm

What is the problem exactly?

kespinko 1-Aug-12 16:02pm

the problem is : I want to select only records with userId = user witch user is in form app right now (like a session).I already can insert data with UserId from logged User but can't view only needed records.I see All users Records.I want see only logged user's records.
Understand me :) . I'm a beginner
sorry for bad explanation

[no name] 1-Aug-12 16:18pm

You complete;y missed the point. What is the exact prolem that you are having? You cannot connect to your database? You cannot construct a query? You do not know how to pass a variable to your query? You do not know how to create a parameterized query? Where is the code that demonstrates your problem?

obp42 1-Aug-12 16:11pm

Have you actually connected your database yet? If so, what are you using to make the connection?

If you haven't, here's a link that should provide a good starting place:
http://www.codeproject.com/Articles/43438/Connect-C-to-MySQL

kespinko 1-Aug-12 16:24pm

I have connection to my DB.Like i told i can insert records.I don't how to select them with where clause.I know how to create Usual select. But don't know how to get a variable from c# and use with "clause" like a parameter name. the code Up in page is the code from gridview "add query".

My connection is :

class ConnectionString
{

public string getString()
{
string server = "localhost";
string database = "HFM";
string uid = "root";
string password = "";
string connectionString;
connectionString = "SERVER=" + server + ";" + "DATABASE=" +
database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";

return connectionString;
}

But i think i dont Have any problem with connection.

[no name] 1-Aug-12 16:41pm

You need to follow the link that Mark put up and see if that resolves your problem.... whatever it is.

2 solutions

Solution 2

Your string is going to look something like this:

C#

String query = "SELECT Value, IdCategory, CreateDate, Description, IdUser FROM"
  + " profit WHERE IdUser = '" + USER + "'";

Make sure you add the single quotes around your user variable like I did.

Then you will want to do something like:

C#

// your connection (conn) has been made at this point
using(MySqlCommand cmd = new MySqlCommand(query, conn))
{
  cmd.CommandText = query;
  MySqlDataReader reader = cmd.ExecuteReader();

  while(reader.Read())
  {
    // assign results to a variable, probably an array of strings
    // using reader["Value"], reader["IdCategory"], etc...
  }

  reader.Close();
  conn.Close();
}

This is assuming you're using MySql Connect/NET, since you haven't specified. I have basically just provided a simplified version of the article in the link I gave in the comments. It's a good pretty good example - between what I've given you and that article you should be able to get this done.

Here's the link again:
Connect C# to MySQL[^]

Posted 1-Aug-12 11:01am

obp42

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**R. Giskard Reventlov** · Accepted Answer · 2012-08-01T10:20:00

Solution 1

Start here[^].

Posted 1-Aug-12 10:20am

R. Giskard Reventlov