MySQL是一種開源的關系型數據庫管理系統，用于管理和存儲數據。在MySQL中，我們可以通過編寫SQL語句來完成各種數據操作和計算，包括乘法表。下面是MySQL實現九九乘法表的代碼：

SELECT 
CONCAT_WS("\t", num1, "x", num2, "=", num1*num2) AS result
FROM 
(SELECT @i := @i + 1 AS num1 FROM (SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t1, (SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t2, (SELECT @i:=0) t3) t4 
CROSS JOIN 
(SELECT @j := @j + 1 AS num2 FROM (SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t1, (SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) t2, (SELECT @j:=0) t3) t5 
WHERE 
num1 >= num2;

以上代碼中，我們首先使用SELECT語句來生成num1和num2兩個數列，它們分別從0到9進行排列組合，生成了100個數字組合。然后我們使用CROSS JOIN將這兩個數列進行笛卡爾積運算，生成了每兩個數字之間的所有組合。最后我們使用WHERE語句過濾掉乘法表中的重復值，從而得到了完整的九九乘法表。