SQL error in Access 2010 - ms-access-2010

Question

I have created a Form in MSAccess 2010 and when running I am getting following error :
The select statement includes a reserved word or an argument name that is misspelled or missing, or the punctuation is incorrect.
The name of my Database is Accessexp
Here is my code:
Private Sub SearchButton_Click()
Dim dbs As Database
Dim rs As Recordset
Dim qdf As QueryDef
Dim productName As String
Dim lastNQuarters As String
Dim strSql As String
Dim columns As String
Dim compstr As String
Dim curstr As String
Dim timestr As String
Dim tablestr As String
Dim sumstr As String
Dim varItem As Variant
Dim compcount As Integer
Dim colcount As Integer
Dim errorcount As Integer
Dim Monthvalue As String
Set dbs = CurrentDb()
errorcount = 0
colcount = 0
lastNQuarters = Me!quarterbox.Value
tablestr = ""
timestr = Me!Monthbox.Value
MsgBox (timestr)
tablestr = "Q" & lastNQuarters
For Each varItem In Me!columnlist.ItemsSelected
If Me!columnlist.ItemData(varItem) <> "---" Then
columns = columns & "," & Chr(34) & Me!columnlist.ItemData(varItem) & Chr(34)
colcount = colcount + 1
End If
Next varItem
compcount = 0
For Each varItem In Me!practicelist.ItemsSelected
compstr = compstr & "," & Chr(34) & Me!practicelist.ItemData(varItem) & Chr(34)
compcount = compcount + 1
Next varItem
If compcount = 0 Then MsgBox ("Warning: No Practice Selected"): errorcount = errorcount + 1
If colcount = 0 Then MsgBox ("Warning: No Practice Selected"): errorcount = errorcount + 1
If errorcount = 0 Then
lastNQuarters = Me!quarterbox.Value
strSql = "Select " & columns & ", " & tablestr & " from Accessexp where Accessexp.[Quarter] = " & tablestr & " and Accessexp.[Month] = " & timestr & ";"
MsgBox (strSql)
Set rs = dbs.OpenRecordset(strSql, dbOpenSnapshot)
With dbs
Set qdf = .CreateQueryDef("QueryOutput", strSql)
DoCmd.OpenQuery "QueryOutput"
.QueryDefs.Delete "QueryOutput"
End With
dbs.Close
qdf.Close
End If
End Sub
My query is coming like this :
Select ,"Revenue Blended","Revenue Direct" Q4
from Accessexp
where Accessexp.[Quarter] = Q4 and Accessexp.[Month] = April;

Answer 1

Is there any other way to seperate values with commas and not putting in begining
After you've built your string with the leading comma just use
columns = Mid(columns, 2)
to trim off the first character.
Other notes:
Wrap your column names in square brackets, not double quotes
String literals need to be enclosed in quotes.
Your resulting query string should look more like this:
Select [Revenue Blended],[Revenue Direct]
from Accessexp
where Accessexp.[Quarter] = 'Q4' and Accessexp.[Month] = 'April';

Answer 2

Try this updated Code.
Private Sub SearchButton_Click()
Dim dbs As Database, rs As Recordset
Dim qdf As QueryDef
Dim productName As String, lastNQuarters As String
Dim strSql As String, columns As String, compstr As String
Dim curstr As String, timestr As String, tablestr As String
Dim sumstr As String, varItem As Variant
Dim compcount As Integer, colcount As Integer, errorcount As Integer
Dim Monthvalue As String
Set dbs = CurrentDb()
errorcount = 0
colcount = 0
lastNQuarters = Me!quarterbox.Value
tablestr = ""
timestr = Me!Monthbox.Value
MsgBox timestr
tablestr = "Q" & lastNQuarters
For Each varItem In Me!columnlist.ItemsSelected
If Me!columnlist.ItemData(varItem) <> "---" Then
columns = columns & "[" & Me!columnlist.ItemData(varItem) & "],"
colcount = colcount + 1
End If
Next
compcount = 0
For Each varItem In Me!practicelist.ItemsSelected
compstr = compstr & "[" & Me!practicelist.ItemData(varItem) & "],"
compcount = compcount + 1
Next
If compcount = 0 Then
MsgBox ("Warning: No Practice Selected")
errorcount = errorcount + 1
Else
compstr = Left(compstr, Len(compstr)-1)
End If
If colcount = 0 Then
MsgBox ("Warning: No Practice Selected")
errorcount = errorcount + 1
Else
columns = Left(columns, Len(columns)-1)
End If
If errorcount = 0 Then
lastNQuarters = Me!quarterbox.Value
strSql = "SELECT " & columns & " FROM Accessexp WHERE Accessexp.[Quarter] = '" & tablestr & "'" & _
" AND Accessexp.[Month] = '" & timestr & "';"
MsgBox (strSql)
Set rs = dbs.OpenRecordset(strSql, dbOpenSnapshot)
With dbs
Set qdf = .CreateQueryDef("QueryOutput", strSql)
DoCmd.OpenQuery "QueryOutput"
'.QueryDefs.Delete "QueryOutput"
End With
dbs.Close
qdf.Close
End If
End Sub