how to select multiple values in mysql database having multiple conditions - mysql

Question

this is my sample form, what i wanted to happen is that anything i wrote in any field there, when i click search it will filter all the data. For example, when i search for the posted date of "2015/11/26" and having the description of "UNIT" all the details will be shown in the table, but as you can see, even the "2015/11/27" details are also shown because it has a description of "UNIT". I know that the reason is because i was using OR as the operator, but if I use AND, it displays nothing because the other text box like PO number, etc. is empty.
can someone help me please?
thanks in advance!
this is my query sample query
SELECT * FROM tbl_somonitoring
where post_date ='" & posteddate.Text & "'
or po_num ='" & ponumber.Text & "'
or doc_num='" & docnumber.Text & "'
or so_num='" & TextBox1.Text & "'
or tagging='" & tagging.Text & "'
or accnt_name='" & accntname.Text & "'
or address='" & address.Text & "'
or description='" & description.Text & "'
or model_name='" & modelname.Text & "'
or request_qty='" & requestqty.Text & "'
or color='" & color.Text & "'
or amount='" & amount.Text & "'

Answer 1

Maybe you can try this.
Dim commandString as String
if postdate.Text <> Nothing or ponumber.Text <> Nothing or docnumber.Text <> Nothing or TextBox1.Text <> Nothing or tagging.Text <> Nothing or accntname.Text <> Nothing or address.Text <> Nothing or description.Text <> Nothing or modelname.Text <> Nothing or requestqty.Text <> Nothing or colAND.Text <> Nothing or amount.Text <> Nothing Then
cmdstring = cmdstring & "Where "
Dim FirstState as Integer = 0
If postdate.text <> Nothing Then
cmdstring = cmdstring & "post_date = " & posteddate.Text
FirstState+=1
End If
If ponumber.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "po_num = " & ponumber.Text
FirstState+=1
End If
If docnumber.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "doc_num = " & docnumber.Text
FirstState+=1
End If
If TextBox1.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & " so_num = " & TextBox1.Text
FirstState+=1
End If
If tagging.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & " tagging = " & tagging.Text
End If
If accntname.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "accnt_name = " & accntname.Text
FirstState+=1
End If
If address.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "address = " & address.Text
FirstState+=1
End If
If description.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "description = " & description.Text
FirstState+=1
End If
If modelname.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & " model_name = " & modelname.Text
FirstState+=1
End If
If requestqty.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "request_qty = " & requestqty.Text
FirstState+=1
End If
If colAND.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & "colAND = " & colAND.Text
FirstState+=1
End If
If amount.Text <> Nothing Then
If FirstState > 0 Then cmdstring = cmdstring & " AND "
cmdstring = cmdstring & " amount = " & amount.Text
FirstState+=1
End If
End If
dim cmd as MySqlCommand = new MySqlCommand(cmdstring,con)
By that you can check each field and use the proper search query

Answer 2

What you need to be doing is testing like this:
(field1 = val1 or field1 = "")
And
(field2 = val2 or field2 = "")
And
...