将 Access SQL 转换为 MySQL

Posted 2023-03-29

【中文标题】将 Access SQL 转换为 MySQL

【英文标题】：Converting Access SQL to MySQL

【发布时间】：2013-03-26 04:25:38

【问题描述】：

您好，我正在尝试将一些 Access SQL 查询转换为 mysql 查询，但由于我不确定如何转换其中的一些代码，因此遇到了麻烦。请有人帮忙。

1.

SELECT Notices.Promoter, 
Sum(IIf([Notices].[Notice Type]='GRANT PERMIT' Or [Notices].[Notice Type]='GRANT VARIATION' Or [Notices].[Notice Type]='GRANT PAA',1,0)) AS Granted, 
Sum(IIf([Notices].[Notice Type]='REFUSE APPLICATION',1,0)) AS Refused, 
Sum(IIf([Notices].[Permit Status]='Deemed',1,0)) AS Deemed
FROM Notices
GROUP BY Notices.Promoter;

2.

SELECT [Notices].Promoter, 
Sum(IIf([Notices].[Notice Type]='VARIATION',1,0)) AS Variation, 
Sum(IIf([Notices].[Notice Type]='TWO HOURS AFTER',1,0)) AS [Two Hours After],
Sum(IIf([Notices].[Notice Type]='THREE MONTHS',1,0)) AS [Three Months],
Sum(IIf([Notices].[Notice Type]='THREE DAY',1,0)) AS [Three Day], 
Sum(IIf([Notices].[Notice Type]='TEN DAY',1,0)) AS [Ten Day]
FROM Notices
GROUP BY [Notices].Promoter;

Access 数据库和 MySQL 数据库标记相同，我只需要覆盖这两个数据库，以便我得到相同的结果。

【参考方案1】：

访问转义关键字使用[]，但是mysql使用``，mysql可以使用CASE替换IIf。

SELECT `Notices`.Promoter, 
Sum(CASE WHEN `Notices`.`Notice Type`=`VARIATION` THEN 1 ELSE 0 END) AS Variation, 
Sum(CASE WHEN `Notices`.`Notice Type`='TWO HOURS AFTER' THEN 1 ELSE 0 END) AS `Two Hours    After`,
Sum(CASE WHEN `Notices`.`Notice Type`='THREE MONTHS' THEN 1 ELSE 0 END) AS `Three Months`,
Sum(CASE WHEN `Notices`.`Notice Type`='THREE DAY' THEN 1 ELSE 0 END) AS `Three Day`, 
Sum(CASE WHEN `Notices`.`Notice Type`='TEN DAY' THEN 1 ELSE 0 END) AS `Ten Day`
FROM Notices
GROUP BY `Notices`.Promoter;