SQLServer2008中的Groupby和case不起作用。

在使用Group by时，必须将所有非聚合表达式列使用的列明确地写在Group by子句中。如果某列未在Group by子句中指定，则在查询中使用该列的时候会引发错误。下面是一个示例：

SELECT department, SUM(salary) as total_salary FROM employee GROUP BY department ORDER BY total_salary DESC

在使用case时，必须确保所有case表达式列都被注明，例如：

SELECT CASE WHEN quantity > 0 THEN 'In Stock' WHEN quantity = 0 THEN 'Out of Stock' ELSE 'Discontinued' END AS stock_status, category, COUNT(*) AS total_items FROM products GROUP BY CASE WHEN quantity > 0 THEN 'In Stock' WHEN quantity = 0 THEN 'Out of Stock' ELSE 'Discontinued' END, category;