Sugar is Sucrose a Disaccharide, 50/50 combination of Glucose and Fructose.
Dextrose is a Monosaccharide, refined from Corn Starch and is essentially just Glucose. It is less sweet than Sugar.
Corn Syrup is further refined and contains varying percentages of Glucose and Fructose. If higher in Fructose, a Monosaccharide, as in HFCS, it is slightly less sweet that Sugar. Reference material varies. Some describe the general term Corn Syrup as equal to or slightly less sweet than Sugar. As a student, we were told to sub extra sugar for corn syrup because fluid ounce for fluid ounce it required more sugar to make and equal volume of corn syrup. Of course that was 25 years ago and formulations and manufacturing processes change...
So...Just to simplify the discussion, I edited my original post to substitute 1 for 1...JJ
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