sql - 如何获得不明显的值(计数> 1)

Question

我正在尝试(在 SQL Server 2k8 中)获取 TheField 的列表，其中 TheField 存在不止一次。类似于以下内容(除非我知道这是不对的):

SELECT TheField FROM TheTable WHERE COUNT(TheField) > 1

Answer 1

您可以使用 GROUP BY与 HAVING子句:

SELECT TheField, COUNT(*) AS Count
FROM TheTable 
GROUP BY TheField
HAVING COUNT(*) > 1

Specifies a search condition for a group or an aggregate. HAVING can be used only with the SELECT statement. HAVING is typically used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause.