feat: 每日一题 2019-06-19

Author: luzhipeng

daily/2019-06-19.md

@@ -0,0 +1,51 @@
+## 每日一题 - Big Countries
+
+### 信息卡片
+
+- 时间：2019-06-19
+- 题目链接：https://leetcode.com/problems/big-countries/
+- tag：`sql`
+
+### 题目描述
+
+```
+There is a table World
+
++-----------------+------------+------------+--------------+---------------+
+| name            | continent  | area       | population   | gdp           |
++-----------------+------------+------------+--------------+---------------+
+| Afghanistan     | Asia       | 652230     | 25500100     | 20343000      |
+| Albania         | Europe     | 28748      | 2831741      | 12960000      |
+| Algeria         | Africa     | 2381741    | 37100000     | 188681000     |
+| Andorra         | Europe     | 468        | 78115        | 3712000       |
+| Angola          | Africa     | 1246700    | 20609294     | 100990000     |
++-----------------+------------+------------+--------------+---------------+
+A country is big if it has an area of bigger than 3 million square km or a population of more than 25 million.
+
+Write a SQL solution to output big countries' name, population and area.
+
+For example, according to the above table, we should output:
+
++--------------+-------------+--------------+
+| name         | population  | area         |
++--------------+-------------+--------------+
+| Afghanistan  | 25500100    | 652230       |
+| Algeria      | 37100000    | 2381741      |
++--------------+-------------+--------------+
+```
+
+### 参考答案
+
+最基本的sql语句，没什么好讲的。 如果不会的话，说明对基础语法不熟。
+
+参考代码：
+
+```sql
+select name, population, area from World where area > 3000000 or population > 25000000
+
+```
+
+### 其他优秀解答
+```
+暂无
+```

daily/README.md

@@ -59,8 +59,15 @@ tag: `tree`
 
 时间: 2019-06-14
 
-### [114.flatten-binary-tree-to-linked-list](./2019-06-21.md)
+### [big-countries](./2019-06-19.md)
+
+tag: `sql`
+
+时间: 2019-06-19
+
+### [nth-highest-salary](./2019-06-21.md)
 
 tag: `sql`
 
 时间: 2019-06-21
+