阅读之后,这不是Explicit vs Implicit SQL Joins的重复.答案可能是相关的(甚至是相同的),但问题是不同的.
有什么区别,应该分别做些什么?
如果我理解正确的理论,查询优化器应该能够互换使用.
将条件放入JOIN子句与WHERE子句之间是否存在差异(性能,最佳实践等)?
例如...
-- Condition in JOIN
SELECT *
FROM dbo.Customers AS CUS
INNER JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
AND CUS.FirstName = 'John'
-- Condition in WHERE
SELECT *
FROM dbo.Customers AS CUS
INNER JOIN dbo.Orders AS ORD
ON CUS.CustomerID = ORD.CustomerID
WHERE CUS.FirstName = 'John'
Run Code Online (Sandbox Code Playgroud)
您更喜欢哪个(也许是为什么)?