[SQL] FROM多个表与INNER JOIN

2023年8月25日 433次阅读

对多个表进行联合查询有两种写法：

（1）FROM多个表

SELECT
    [a].[NoticeText]    
FROM
    [dbo].[Notice] [a],
    [dbo].[User] [b],
    [dbo].[WechatSE] [c]
WHERE
    [a].[UserID] =[b].[UserID]
    AND [b].[UserID]=[c].[UserID]
    AND [c].[OpenID]=@OpenID

（2）使用INNER JOIN

SELECT [a].[NoticeText]     
    FROM [dbo].[Notice] [a]
        INNER JOIN [dbo].[User] [b] ON [a].[UserID] =[b].[UserID]
        INNER JOIN [dbo].[WechatSE] [c] ON [b].[UserID]=[c].[UserID]
    WHERE [c].[OpenID]=@OpenID