Data type missmatch in criteria expression - sql

Question

Is there any wrong in this SQL statement in VBA:
myConnection.Execute "update item_gallery set quantity = 'qtToTotal' where item = 'Desc' and gallery ='Gallery_Name'"
where
qtToTotal = qtTo + qtFrom
While Not myRecordSetItem.EOF
If !item_ID = myRecordSetItem.Fields("item_ID").Value Then
Desc = myRecordSetItem.Fields("Desc").Value
End If
myRecordSetItem.MoveNext
Wend
While Not myRecordSetGallery.EOF
If !To = myRecordSetGallery.Fields("Gallery_ID").Value Then
Gallery_Name = myRecordSetGallery.Fields("Gallery_Name").Value
End If
myRecordSetGallery.MoveNext
Wend
it always give me the message :
"data type missmatch in criteria expression"

Answer 1

This:
myConnection.Execute "update item_gallery set quantity = 'qtToTotal' where item = 'Desc' and gallery ='Gallery_Name'"
where
qtToTotal = qtTo + qtFrom
Looks like it should read more like this (but I'm not 100% as I have some questions to ask):
myConnection.Execute "UPDATE item_gallery" _
& " SET quantity = qtToTotal" _
& " WHERE item = Desc" _
& " AND gallery = Gallery_Name" _
& " AND qtToTotal = (qtTo + qtFrom)"
My guess is you're getting this error because you've surrounded what look like field names in single quotes ('), which is what you do when you're telling SQL that you're wanting a piece of text rather than one of the fields in your database.
Examples of when to use single quotes:
...when you want to refer to just a piece of text in a field formatted as text:
"SELECT * FROM tblNames WHERE FirstName = 'John'".
...when you want to refer to text that's currently in a field on an open form that is formatted as text:
"SELECT * FROM tblNames WHERE FirstName = '" & Me.txtFirstName & "'".
But in your case it looks like you want a field from the underlying tables, so you don't need any single quotes around the field name.
Your quantity field sounds like it could well be a numeric field and you've essentially asked it to try and put the piece of text "qtToTotal" in the quantity field, which it won't be able to do if that field is only setup to accept numbers.
A few questions though as I suspect there might be more problems here (and I'll update this based on your answers):
Are all these fields...
quantity
qtToTotal
item
Desc
gallery
qtToTotal
qtTo
qtFrom
...located in the table item_gallery?
If they're not then you need to create JOIN(s) in your SQL statement between the item_gallery table and whatever table(s) the other fields come from using a field that matches/relates the records from both tables.
What is the data type for each of these fields?
Where you've used an = between 2 fields, are both those fields the same data type? If not it will cause a mismatch.
Also: I'd advise against using "Desc" as a field name as DESC is a word reserved for "descending order" in an ORDER BY clause in SQL.