sql语句的and和or怎么确定执行的先后顺序呢比如我有一个语句,SELECT * FROM dbo.articles WHERE hit >100 and webID=1 and forumID=302 or webID=2 and forumID=14我想得到的优先顺序为 where hit > 100 and [(webID=1 and forumID=3
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![sql语句的and和or怎么确定执行的先后顺序呢比如我有一个语句,SELECT * FROM dbo.articles WHERE hit >100 and webID=1 and forumID=302 or webID=2 and forumID=14我想得到的优先顺序为 where hit > 100 and [(webID=1 and forumID=3](/uploads/image/z/14715077-5-7.jpg?t=sql%E8%AF%AD%E5%8F%A5%E7%9A%84and%E5%92%8Cor%E6%80%8E%E4%B9%88%E7%A1%AE%E5%AE%9A%E6%89%A7%E8%A1%8C%E7%9A%84%E5%85%88%E5%90%8E%E9%A1%BA%E5%BA%8F%E5%91%A2%E6%AF%94%E5%A6%82%E6%88%91%E6%9C%89%E4%B8%80%E4%B8%AA%E8%AF%AD%E5%8F%A5%2CSELECT+%2A+FROM+dbo.articles+WHERE+hit+%3E100+and+webID%3D1+and+forumID%3D302+or+webID%3D2+and+forumID%3D14%E6%88%91%E6%83%B3%E5%BE%97%E5%88%B0%E7%9A%84%E4%BC%98%E5%85%88%E9%A1%BA%E5%BA%8F%E4%B8%BA+where+hit+%3E+100+and+%5B%28webID%3D1+and+forumID%3D3)
sql语句的and和or怎么确定执行的先后顺序呢比如我有一个语句,SELECT * FROM dbo.articles WHERE hit >100 and webID=1 and forumID=302 or webID=2 and forumID=14我想得到的优先顺序为 where hit > 100 and [(webID=1 and forumID=3
sql语句的and和or怎么确定执行的先后顺序呢
比如我有一个语句,SELECT * FROM dbo.articles WHERE hit >100 and webID=1 and forumID=302 or webID=2 and forumID=14
我想得到的优先顺序为 where hit > 100 and [(webID=1 and forumID=302) or (webID=2 and forumID=14)]
其中两个小括号内的条件是并列的,中括号和外面的部分是并列的.
怎么来约束这个关系呢?
sql语句的and和or怎么确定执行的先后顺序呢比如我有一个语句,SELECT * FROM dbo.articles WHERE hit >100 and webID=1 and forumID=302 or webID=2 and forumID=14我想得到的优先顺序为 where hit > 100 and [(webID=1 and forumID=3
在SQL语句中,AND的优先级要高于OR的优先级,因此,要实现这种执行的先后顺序,需要使用括号
SELECT * FROM dbo.articles WHERE hit >100 and (webID=1 and forumID=302 or webID=2 and forumID=14)