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mysql selecting with join to dataset and datatable in c#

I searched a lot but could not find the right solution.
Lets say ill select data like:
using(MySqlConnection connection = new MySqlConnection(MyConnectionString))
using(MySqlCommand cmd = connection.CreateCommand())
{
connection.Open();
cmd.CommandText = "SELECT a.Id, a.Foo, b.Bar FROM tableA a, tableB b where a.Id = b.Id";
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
DataTable dt = ds.Tables[...]; //<== here is the problem
}
and I want to add this to a datatable,
How do I call the table in this case ?
Is it tableA ?
Does it matters how I name it ? (could I name it foobar as well???)

It is unclear what you are really asking for, but due to the length of comment and clarification, putting into an answer.
If you are trying to get multiple query results back from MySQL into a single "DataSet" (which can contain multiple tables), your query could contain multiple sql-statements and each would be returned into the dataset for you as different table results. For example, if you did something like...
using(MySqlConnection connection = new MySqlConnection(MyConnectionString))
using(MySqlCommand cmd = connection.CreateCommand())
{
connection.Open();
cmd.CommandText =
#"select * from TableA;
select * from TableB;
SELECT a.Id, a.Foo, b.Bar FROM tableA a, tableB b where a.Id = b.Id;";
MySqlDataAdapter da = new MySqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds);
}
Your dataset would have 3 tables in it in direct correlation of the queries provided..
ds.Tables[0] = result of tableA all records.
ds.Tables[1] = result of tableB all records.
ds.Tables[2] = result of JOIN query tableA and tableB.
you could then refer to them locally however you need to...
ds.Tables[0].TableName = "anyLocalTableNameReference".
var t1Recs = ds.Tables[0].Rows.Count;
etc... or even create your own individual datatable variable name without having to explicitly reference the dataset and table array reference
DataTable myLocalTableA = ds.Tables[0];
DataTable myLocalTableB = ds.Tables[1];
DataTable myJoinResult = ds.Tables[2];
Hopefully this clarifies a bunch with the querying and referencing of multiple data results returned and how to then reference to the tables individually.

Create Table or DataSet from relation between 2 Tables in same DataSet

I've been stuck on this all day.... My love to the person who can solve it!!!!
So, there are 2 Tables
Access Table in (ds.Tables["Access"]) which contains columns of
Barcode, Description, quantity in warehouse etc
and Excel Table in (ds.Tables["Excel"]) which contains columns of
Barcode, quantiy ordered etc however named F2,F4,F8
So how do I get a final DataTable/DataSet (anything that I can .DataSource to on DataGridView) with Excel and Access matched on Barcode????
OleDbConnection conAccess = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\PROGRAMMING.LAB\\geekx_recent.mdb");
OleDbDataAdapter daAccess = new OleDbDataAdapter("Select Barcode AS BARCODE, quantity AS QTY_WH From Stock", conAccess);
DataSet dsAll = new DataSet();
daAccess.Fill(dsAll, "Access");
OleDbConnection conExcel = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\PROGRAMMING.LAB\\order.xlsx;Extended Properties = Excel 12.0 Xml");
OleDbDataAdapter daExcel = new OleDbDataAdapter("SELECT F2 AS BARCODE, F8 AS ORDER_CUST FROM [phil$] WHERE ISNUMERIC(F8)",conExcel);
daExcel.Fill(dsAll, "Excel");
DataRelation dr = dsAll.Relations.Add("Excel_Access", dsAll.Tables["Excel"].Columns["BARCODE"], dsAll.Tables["Access"].Columns["BARCODE"], false);
DataTable dtExcel = dsAll.Tables["Excel"];
DataTable dtAccess = dsAll.Tables["Access"];
DataTable dtAll = new DataTable();
var query = from ex in dtExcel.AsEnumerable()
join ac in dtAccess.AsEnumerable()
on ex.Field<string>("BARCODE") equals ac.Field<string>("BARCODE")
select new
{
Order = ex.Field<string>("ORDER_CUST"),
Stock = ac.Field<string>("QTY_WH"),
Barcode = ex.Field<string>("BARCODE")
};
foreach (var q in query)
{
dtAll.Rows.Add(q.Barcode, q.Stock, q.Order);
}
dataGridView1.DataSource = dtAll;
This returns
An unhandled exception of type 'System.InvalidCastException' occurred in System.Data.DataSetExtensions.dll
Additional information: Unable to cast object of type 'System.Double' to type 'System.String'.
At the select new block
Any ideas anyone?

See code below and following webpage for joining tables : https://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
DataTable dt1 = new DataTable();
DataTable dt2 = new DataTable();
var results =
from c1 in dt1.AsEnumerable()
join c2 in dt2.AsEnumerable()
on c1.Field<int>("ID") equals c2.Field<int>("ID") into cs
select new { Category = c1.Field<string>("ColB"), Fields = cs };

Show multiples table results of stored procedure in c# datagridview

SqlCommand Mysqlcommand = new SqlCommand();
if (MyConnection.State == ConnectionState.Closed)
{
MyConnection.Open();
}
Mysqlcommand.Connection = MyConnection;
Mysqlcommand.CommandText = MysqlQuery;
Mysqlcommand.CommandTimeout = 120;
SqlDataReader MySqlDataReader;
MySqlDataReader = Mysqlcommand.ExecuteReader();
bindingSource4.DataSource = MySqlDataReader;
gridview.DataSource = bindingSource4;
I would like to have the datagridview as on example image:

Welcome to StackOverflow,
I would recommend you to first execute this command in SQL:
SELECT a.Sr, a.[International Tender], a.Total, b.[Domestic Tender], b.Total,
c.[News Automation],c.Total, d.[News Manual], d.Total
FROM
tableA a
inner join
tableB b
ON a.Sr = b.Sr
inner join
TableC c
ON b.[Domestic Tender] = c.[News Automation]
inner join
TableD d
ON c.[News Automation] = d.[News Manual]
If it meets your expectations I can then turn it into C# code to set it as datagridview source

how to display value of column from another table

How do I display the value of column Department from tblDepartment to tblEmployee in a webform table? I have this code but it only displays the DeptID.
This is the Page_load code
sConn = new SqlConnection(sStr);
daEmp = new SqlDataAdapter("SELECT * FROM tblEmployee", sConn);
daDep = new SqlDataAdapter("SELECT * FROM tblDepartment", sConn);
dsEmp = new DataSet();
dsDep = new DataSet();
daEmp.Fill(dsEmp, "tblEmployee");
daDep.Fill(dsDep, "tblDepartment");
dsEmp.Tables["tblEmployee"].PrimaryKey = new DataColumn[] { dsEmp.Tables["tblEmployee"].Columns["EmployeeID"] };
DataTable dt = new DataTable();
dgvEmployee.DataSource = dsEmp.Tables["tblEmployee"];
dgvEmployee.DataBind();
These are the tables

When you need to display information from two or more different tables you can join them based on relationship(primary key and foreign key) columns:
You need to Replace this Query:
SELECT * FROM tblEmployee
With this:
SELECT employee.*,department.Department
FROM tblEmployee employee
INNER JOIN tblDepartment department ON employee.DeptID=department.DeptID

Using SqlDataAdapter to insert a row

I want to insert a row into the Database using SqlDataAdapter. I've 2 tables (Custormers & Orders) in CustomerOrders database and has more than thousand records. I want to create a GUI (TextBoxes) for adding new customer & orders into the Database to their respective tables.
How should I do it?
I guess the method that is usually followed is
dataAdapter = new SqlDataAdapter (sqlQuery, conn);
dataSet = new DataSet();
da.Fill(dataSet);
Now take the values from textboxes (or use DataBinding) to add a new row into the dataSet and call
da.Update(dataSet);
But the Question is Why should I fetch all other records into dataSet using da.Fill(dataSet ) in the first place? I just want to add a single new record.
For this purpose what I'm doing is, Creating the schema of the Database in the DataSet. like this:
DataSet customerOrders = new DataSet("CustomerOrders");
DataTable customers = customerOrders.Tables.Add("Customers");
DataTable orders = customerOrders.Tables.Add("Orders");
customers.Columns.Add("CustomerID", Type.GetType("System.Int32"));
customers.Columns.Add("FirstName", Type.GetType("System.String"));
customers.Columns.Add("LastName", Type.GetType("System.String"));
customers.Columns.Add("Phone", Type.GetType("System.String"));
customers.Columns.Add("Email", Type.GetType("System.String"));
orders.Columns.Add("CustomerID", Type.GetType("System.Int32"));
orders.Columns.Add("OrderID", Type.GetType("System.Int32"));
orders.Columns.Add("OrderAmount", Type.GetType("System.Double"));
orders.Columns.Add("OrderDate", Type.GetType("System.DateTime"));
customerOrders.Relations.Add("Cust_Order_Rel", customerOrders.Tables["Customers"].Columns["CustomerID"], customerOrders.Tables["Orders"].Columns["CustomerID"]);
I used DataBinding to bind these columns to respective text boxes.
Now I'm confused! What should I do next? How to use Insert command? Because I didn't give any dataAdapter.SelectCommand so dataAdapter.Update() wont work I guess. Please suggest a correct approach.

Set the select command with a "0 = 1" filter and use an SqlCommandBuilder so that the insert command is automatically generated for you.
var sqlQuery = "select * from Customers where 0 = 1";
dataAdapter = new SqlDataAdapter(sqlQuery, conn);
dataSet = new DataSet();
dataAdapter.Fill(dataSet);
var newRow = dataSet.Tables["Customers"].NewRow();
newRow["CustomerID"] = 55;
dataSet.Tables["Customers"].Rows.Add(newRow);
new SqlCommandBuilder(dataAdapter);
dataAdapter.Update(dataSet);

You can fill the dataSet with an empty set e.g.:
da = new SqlDataAdapter ("SELECT * FROM Customers WHERE id = -1", conn);
dataSet = new DataSet();
da.Fill(dataSet);
Then you add your rows and call update.
For this scenario though it would probably be better not to use SqlDataAdapter. Instead use the SqlCommand object directly for insertion. (Even better, use LINQ to SQL or any other ORM)

SqlConnection con = new SqlConnection("Data Source=(local);Initial Catalog=test;Integrated Security=True");
SqlDataAdapter da=new SqlDataAdapter("Insert Into Employee values("+textBox1.Text+",'"+textBox2.Text+"','"+textBox3.Text+"',"+textBox4.Text+")",con);
DataSet ds = new DataSet();
da.Fill(ds);
I have to do first time. You can try it . It works well.