项目描述
X 市建了一个新的体育馆，每日人流量信息被记录在这三列信息中：序号 (id)、日期 (date)、 人流量 (people)。
请编写一个查询语句，找出高峰期时段，要求连续三天及以上，并且每天人流量均不少于100。
例如，表 stadium：
+------+------------+-----------+
| id | date | people |
+------+------------+-----------+
| 1 | 2017-01-01 | 10 |
| 2 | 2017-01-02 | 109 |
| 3 | 2017-01-03 | 150 |
| 4 | 2017-01-04 | 99 |
| 5 | 2017-01-05 | 145 |
| 6 | 2017-01-06 | 1455 |
| 7 | 2017-01-07 | 199 |
| 8 | 2017-01-08 | 188 |
+------+------------+-----------+
对于上面的示例数据，输出为：
+------+------------+-----------+
| id | date | people |
+------+------------+-----------+
| 5 | 2017-01-05 | 145 |
| 6 | 2017-01-06 | 1455 |
| 7 | 2017-01-07 | 199 |
| 8 | 2017-01-08 | 188 |
+------+------------+-----------+
Note:
每天只有一行记录，日期随着 id 的增加而增加。
SQL Server版:
DECLARE @sid INT;
DECLARE @sdate DATE;
DECLARE @speople INT;
DECLARE @startdate DATE;
DECLARE @nextdate Date;
DECLARE @thisN INT =0;
DECLARE my_coursor CURSOR FOR SELECT id,date,people FROM stadium WHERE people >=100
OPEN my_coursor
FETCH NEXT FROM my_coursor INTO @sid ,@sdate,@speople;
SET @startDate=@sdate;
SET @nextDate=@sdate;
WHILE @@FETCH_STATUS=0
BEGIN
IF(@sdate = DATEADD(DAY,1,@nextDate))
BEGIN
SET @nextDate=@sdate;
SET @thisN=@thisN+1;
END
ELSE
BEGIN
SET @startDate=@sdate;
SET @nextDate=@sdate;
SET @thisN=0;
END
FETCH NEXT FROM my_coursor INTO @sid,@sdate,@speople;
END
CLOSE my_coursor;
DEALLOCATE my_coursor;
IF(@thisN>=3)
BEGIN
SELECT * FROM dbo.stadium WHERE date>=@startDate AND date <=@nextDate
END
