MySql executing Set and Concat statements in VB.net - mysql

Question

I am trying to get some values - columns as rows and viceversa - from MySQL to show on a DataGridView. I have this code, that should be run in MySQL-
SET #header = CONCAT('SELECT \'sl\', ',
(SELECT GROUP_CONCAT(CONCAT(' \'', sl, '\'')) FROM cars where sl=1),
' LIMIT 0, 0');
SET #a = -1;
SET #line1 = CONCAT(
'SELECT \'Plate\',',
(
SELECT GROUP_CONCAT(
CONCAT(' (SELECT Plate FROM cars LIMIT ',
#a:=#a+1,
', 1)')
)
FROM cars where sl=1
));
SET #a := -1;
SET #line2 = CONCAT(
'SELECT \'Brand\',',
(
SELECT GROUP_CONCAT(
CONCAT(' (SELECT Brand FROM cars LIMIT ',
#a:=#a+1,
', 1)')
)
FROM cars where sl=1
));
SET #query = CONCAT('(',
#header,
') UNION (',
#line1,
') UNION (',
#line2,
')'
);
PREPARE my_query FROM #query;
EXECUTE my_query;
Now when I try to run this via the ExecuteNonQuery command by saving all this code in a string, I get a MySQLException error- Fatal error encountered during command execution.
I have tried to split the code into separate strings, but the same error popped. Also tried to increase the CommandTimeout, but nothing worked.
Is there any special way to run these statements? Or is there any problem with the code? Please note that this runs effectively without any error on the command line client.
PS: The code is used from Q# 3288014 - Thanks to Anax
EDIT:
I found a work around to the same thing, but all done in VB.
Dim sa() As String = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
Dim sa2() As String = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
connect()
Dim reader As MySqlDataReader
execstr = "describe cars"
Dim cmd As New MySqlCommand(execstr, connection)
reader = cmd.ExecuteReader()
Dim i As Integer = 0
While reader.Read
sa(i) = reader.GetString(0)
i = i + 1
End While
reader.Close()
connection.Close()
connect()
execstr = "select*from cars where sl=1;"
Dim cmd2 As New MySqlCommand(execstr, connection)
reader = cmd2.ExecuteReader()
While reader.Read
For i1 As Integer = 0 To sa.Length - 1
sa2(i1) = reader.GetString(i1)
Next
End While
reader.Close()
connection.Close()
reader.Close()
connection.Close()
Dim t As New DataTable
t.Columns.Add(sa(0))
t.Columns.Add(sa2(0))
For y As Integer = 1 To sa.Length - 1
t.Rows.Add(sa(y), sa2(y))
Next
DataGridView1.DataSource = t
Funny to find that what all can be done in a string in MySQL, takes so much code in VB.

Answer 1

You can't do that in a single or series of ExecuteNonQuery command(s). This example was showing the code you would put in a stored procedure on mysql. The you call the stored procedure using a DataAdapter or DataReader.