"content":"<p>Table: <code>MyNumbers</code></p>\n\n<pre>\n+-------------+------+\n| Column Name | Type |\n+-------------+------+\n| num | int |\n+-------------+------+\nThis table may contain duplicates (In other words, there is no primary key for this table in SQL).\nEach row of this table contains an integer.\n</pre>\n\n<p> </p>\n\n<p>A <strong>single number</strong> is a number that appeared only once in the <code>MyNumbers</code> table.</p>\n\n<p>Find the largest <strong>single number</strong>. If there is no <strong>single number</strong>, report <code>null</code>.</p>\n\n<p>The result format is in the following example.</p>\n<ptable> </ptable>\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nMyNumbers table:\n+-----+\n| num |\n+-----+\n| 8 |\n| 8 |\n| 3 |\n| 3 |\n| 1 |\n| 4 |\n| 5 |\n| 6 |\n+-----+\n<strong>Output:</strong> \n+-----+\n| num |\n+-----+\n| 6 |\n+-----+\n<strong>Explanation:</strong> The single numbers are 1, 4, 5, and 6.\nSince 6 is the largest single number, we return it.\n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> \nMyNumbers table:\n+-----+\n| num |\n+-----+\n| 8 |\n| 8 |\n| 7 |\n| 7 |\n| 3 |\n| 3 |\n| 3 |\n+-----+\n<strong>Output:</strong> \n+------+\n| num |\n+------+\n| null |\n+------+\n<strong>Explanation:</strong> There are no single numbers in the input table so we return null.\n</pre>\n",