Correct answer:

When J is between -999,999,999 and -100,000,000 or between 1,000,000,000 and 2,147,483,647

Correct explanation:

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If the expression is between -999,999,999 and -1(,0)00,000,000 or between 1,000,000,000 and 2,147,483,647 it's decial representation requires exactly 10 didits, so it will just fit into a 10 character string with no paddiing with spaces either side; so the strings STR(J) and cast(J as char(10)) are both the correct decimal representation of J, hence both the same and the expression evaluates to TRUE in this case.