a problem with dim a variable in access vba 2010

i try to copy this code to a  field but when i run this code i get in the field only the word "false"

 why is this do is a limit in the length from a string

Dim SqlPart1 As String
Dim SqlPart2 As String
Dim SqlStatement2 As String
Dim Where As String

SqlPart1 = " SELECT InvoicesDetailsAndInvoicesZikuiDetailsListQ.Product, Sum(InvoicesDetailsAndInvoicesZikuiDetailsListQ.Qty) AS SumOfQty, " & _
                " InvoicesDetailsAndInvoicesZikuiDetailsListQ.Price, InvoicesDetailsAndInvoicesZikuiDetailsListQ.commission, " & _
                " Sum([qty]*[price]) AS Total, IIf([invoicet.maam]<>0,True,False) AS TaxCheckBox, InvoiceT.Customer, " & _
                " InvoicesDetailsAndInvoicesZikuiDetailsListQ.maam " & _
                " FROM InvoicesDetailsAndInvoicesZikuiDetailsListQ INNER JOIN InvoiceT ON InvoicesDetailsAndInvoicesZikuiDetailsListQ.InvoiceID = InvoiceT.InvoiceID " & _
SqlPart2 = " GROUP BY InvoicesDetailsAndInvoicesZikuiDetailsListQ.Product, InvoicesDetailsAndInvoicesZikuiDetailsListQ.Price, " & _
                " InvoicesDetailsAndInvoicesZikuiDetailsListQ.commission, " & _
                " IIf([invoicet.maam]<>0,True,False), InvoiceT.Customer, InvoicesDetailsAndInvoicesZikuiDetailsListQ.maam "
 SqlStatement2 = " SELECT InvoiceID, Product, Qty as sumofqty, Price, total, commission, Customer, OrderDate " & _
                " FROM InvoicesDetailsAndInvoicesZikuiDetailsListQ "
Text0 = SqlPart1 & SqlPart2
End Sub

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