8. Let $a_{1}, a_{2}, a_{3}, a_{4}$ be any permutation of $1,2,3,4$, and $f$ be a mapping from $\{1,2,3,4\}$ to $\{1,2,3,4\}$ such that $f(i) \neq i$. Denote the number table $\left[\begin{array}{cccc}a_{1} & a_{2} & a_{3} & a_{4} \\ f\left(a_{1}\right) & f\left(a_{2}\right) & f\left(a_{3}\right) & f\left(a_{4}\right)\end{array}\right]$. If the corresponding positions of number tables $M$ and $N$ have at least one difference, then $M$ and $N$ are said to be two different number tables. The number of different number tables that satisfy the condition is . $\qquad$
8. 216 Detailed Explanation: For a permutation of $a_{1}, a_{2}, a_{3}, a_{4}$, there can be 9 mappings satisfying $f(i) \neq i$. Since $a_{1}, a_{2}, a_{3}, a_{4}$ have $A_{4}^{4}=24$ permutations, the total number of number tables satisfying the condition is $24 \times 9=216$.