Hany Helmy (6/14/2015)
Nice tricky question, thanx.
I thought it was quite a nice question.
It seemed pretty trick-free to me, although you did have to remember three facts: (i) that UNION is a set operation (unlike UNION ALL, which is a bag operation), (ii) that integers used in a string context are converted automatically to string, and (iii) that 1234512345 is small enough to be representable in the INT type.