type mismatch

[seeker63]

Why would this line of code throw a type mismatch error?

Dim sSQL2 as String
sSQL2 = "Select * from dbo.TradeTransPrimary where combinedso = '" + cSO + "' AND marketingfirm = '2'"


as i leave the line that populates sSQL2 a type mismatch error is given.

[pbaldy]

Try & instead of + as a concatenation operator.

[Bob Fitz]

Not sure my observations are valid, but, if marketingfirm is actually numeric, then the single quotes around 2 are not needed.
What are the + signs for?