我只是想知道如何计算特定设备的数量..
SELECT
EQUIPMENTS.DESCRIPTION AS [EQUIPMENT TYPE],
Count(EQUIPMENTS.EQNAME) AS QUANTITY,
(SELECT Count(EQUIPMENTS.CONDITION) FROM EQUIPMENTS WHERE EQUIPMENTS.CONDITION = 'Functional') AS WORKING,
(SELECT Count(EQUIPMENTS.CONDITION) FROM EQUIPMENTS WHERE EQUIPMENTS.CONDITION = 'Non-Functional') AS [NON-WORKING]
FROM EQUIPMENTS
GROUP BY EQUIPMENTS.DESCRIPTION;
此查询返回以下内容:
EQUIPMENT NAME : PROJECTOR
QUANTITY : 3
WORKING : 2
NON-WORKING :1
现在,如果我添加另一个具有不同类型的设备,例如计算器,它将具有相同的 WORKING 和 NON-WORKING 计数,仅适用于 PROJECTOR。我该如何让它也计算计算器的数量以及工作和非工作本身的数量?我的意思是每当我添加另一个具有特定描述的设备时,查询也会独立计算它吗?
我正在使用 VB.NET,这个查询是在 MS ACCESS 2007 中进行的。