g0601_0700.s0619_biggest_single_number.readme.md Maven / Gradle / Ivy
619\. Biggest Single Number
Easy
SQL Schema
Table: `MyNumbers`
    +-------------+------+ 
    | Column Name | Type | 
    +-------------+------+ 
    | num         | int  |
    +-------------+------+ 
There is no primary key for this table. It may contain duplicates.
Each row of this table contains an integer.
A **single number** is a number that appeared only once in the `MyNumbers` table.
Write an SQL query to report the largest **single number**. If there is no **single number**, report `null`.
The query result format is in the following example.
**Example 1:**
**Input:** MyNumbers table: 
    +-----+ 
    | num | 
    +-----+ 
    | 8   | 
    | 8   | 
    | 3   | 
    | 3   | 
    | 1   | 
    | 4   | 
    | 5   | 
    | 6   | 
    +-----+
**Output:** 
    +-----+ 
    | num | 
    +-----+ 
    | 6   | 
    +-----+
**Explanation:** The single numbers are 1, 4, 5, and 6. Since 6 is the largest single number, we return it.
**Example 2:**
**Input:** MyNumbers table: 
    +-----+ 
    | num | 
    +-----+ 
    | 8   | 
    | 8   | 
    | 7   | 
    | 7   | 
    | 3   | 
    | 3   | 
    | 3   | 
    +-----+
**Output:** 
    +------+ 
    | num  | 
    +------+ 
    | null | 
    +------+
**Explanation:** There are no single numbers in the input table so we return null.     © 2015 - 2025 Weber Informatics LLC | Privacy Policy