How to read specific column and cell in mysql in c#?

Question

I use ExecuteReader to select all (SELECT*) for all field like this

string query = "SELECT* FROM tb_patient_information ";
        if (this.OpenConnection() == true)
        { //Create Command
            MySqlCommand cmd = new MySqlCommand(query, connection);
            //Create a data reader and Execute the command
            MySqlDataReader dataReader = cmd.ExecuteReader();
            while (dataReader.Read())
            { ... }

but I only want to select in specific column and cell like in red square.. like this picture

Why not use mysql to achieve the column part? SELECT [ColumnName] FROM tb_patient_information — Ash, Apr 09 '13 at 14:17
Suggestion: Never use * to select in your programs, specify the column names specifically. This way your program won't crash or have unexpected functionality if the table changes (and you don't have to remember to change several things). — David S., Apr 09 '13 at 14:17
but I only want to select in specific column and cell like in red square — Prasetyo Jean, Apr 09 '13 at 14:51

John Woo · Answer 1 · 2013-04-09T15:05:10.300

3

You can get the specific column inside the while clause.

while (dataReader.Read())
{ 
    var _column = dataReader["Nama_Kategori"];
}

edited Apr 09 '13 at 15:05

answered Apr 09 '13 at 14:15

John Woo

258,903
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but I only want to select in specific column and cell like in red square (see my picture) – Prasetyo Jean Apr 09 '13 at 15:04
why are you not filtering the result with `WHERE` clause eg `SELECT * FROM tb_patient_information WHERE ID_Kategori = 'KI-02'`? – John Woo Apr 09 '13 at 15:05
I mean : SELECT* FROM tb_patient_information .so this code will display many line, and I only want to select 3rd line.. – Prasetyo Jean Apr 09 '13 at 15:11
yes, it selects all records, why not filter it using `WHERE`? – John Woo Apr 09 '13 at 15:12

score 1 · Answer 2 · answered Apr 09 '13 at 14:18

Consider using

        string query = "SELECT column FROM tb_patient_information ";
        if (this.OpenConnection() == true)
        { 
            //Create Command
            MySqlCommand cmd = new MySqlCommand(query, connection);
            //Create a data reader and Execute the command
            MySqlDataReader dataReader = cmd.ExecuteReader();
            if (dataReader.Read())
            { 
                dataReader.ExecuteScalar();
             }
        }

or use dataReader["columnName"]

but I only want to select in specific column and cell like in red square (see my picture) — Prasetyo Jean, Apr 09 '13 at 15:05

Alex · Answer 3 · 2013-04-10T04:31:15.177

1

You can use ExecuteScalar() of MySqlCommand method to retieve single value

MySqlCommand myCommand = new MySqlCommand("SELECT Nama_Kategori FROM tb_patient_information WHERE Id_kategori = 'KI-02'", myConnection);
myCommand.Connection.Open();
myCommand.ExecuteScalar();
myConnection.Close();

edited Apr 10 '13 at 04:31

answered Apr 09 '13 at 14:21

Alex

8,827
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but I only want to select in specific column and cell like in red square (see my picture) – Prasetyo Jean Apr 09 '13 at 15:05
Thank you @voo but TOP only in SQL not in mySQL – Prasetyo Jean Apr 09 '13 at 23:47
@YanPayjo If your Id_kategori is a primary key, then making it a select field will return you only 1 row without TOP – Alex Apr 10 '13 at 04:32

Pandian · Answer 4 · 2013-04-09T16:46:59.423

SQL Query

If you want only third row data then try the below query :

Select * from (Select row_number() over (order by subssn) as rownum, * FROM 
tb_patient_information)result Where rownum = 3

-This Query return the 3rd row on Result Set

In DataReader

while (dataReader.Read())
{ 
string Id = dataReader["Id_kategori"].ToString();
string Name = dataReader["Nama_Kategori"].ToString();
}

OR IF You Say I only use Select * from tb_patient_information and i need 3rd row result Then try like below

         int count=1;  
         while (dataReader.Read())  
          {  

            if(count == 3)
            {
             string Id = dataReader["Id_kategori"].ToString();
             string Name = dataReader["Nama_Kategori"].ToString();
            }  
           count ++;  
          }

but I only want to select in specific column and cell like in red square (see my picture) — Prasetyo Jean, Apr 09 '13 at 15:04

How to read specific column and cell in mysql in c#?

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