Question

我正在开发一个T-SQL查询（我正在运行一个SQL Server数据库），它应该从一个值列表中计算中值。查询如下所示：

SELECT 
   PERCENTILE_CONT(0.5) OVER (ORDER BY age) as Age 
FROM 
   peopleDB 
WHERE 
   <expressions>;

数据库有100行。查询返回中位数（相同值）100次，但我的目标是只返回一次。我一直试图以各种方式使用DISTINCT和GROUP BY，但每次都会返回语法错误。目前数据库不支持DISTINCT。

我有没有机会忽视一些明显的东西？

Answer 1

我从未听说过TSL。但是，下列之一可能有效：

SELECT PERCENTILE_CONT(0.5) OVER (ORDER BY age) as Age
FROM peopleDB
WHERE <expressions>
limit 1;

SELECT top 1 PERCENTILE_CONT(0.5) OVER (ORDER BY age) as Age
FROM peopleDB
WHERE <expressions>;

SELECT max(PERCENTILE_CONT(0.5) OVER (ORDER BY age)) as Age
FROM peopleDB
WHERE <expressions>;

select max(age)
from (SELECT top 1 PERCENTILE_CONT(0.5) OVER (ORDER BY age) as Age
      FROM peopleDB
      WHERE <expressions>
     ) t

Answer 2

尝试一个空的over子句。

SELECT 
   PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY <column>) OVER () as Age 
FROM 
   peopleDB 
WHERE 
   <expressions>;

Answer 3

我遇到了同样的问题＆amp;阅读这有助于我实现解决方案。因此，对您的问题的SQL语法（因为我不熟悉TSQL）是：

UITableViewController

为我工作！

TSL / SQL PERCENTILE_CONT应返回1条记录

3 个答案: