连接两个选择语句

Question

有人可以请给我一些关于如何加入以下两个选择语句的建议：

SELECT TOP 200 * 
FROM dbo.Creation_LimitsAndExclusions WITH (nolock) 
WHERE LeagueCodeID = 37

和

select * 
from dbo.Creation_Markets with (nolock) 
where ClassID = 9 and IsParentMatch = 1

提前致谢。

Answer 1

我不知道键是什么，但是如果两个表中的键都是 CreationID，则连接将如下所示：

SELECT TOP 200 * 
FROM dbo.Creation_LimitsAndExclusions WITH (nolock) 
LEFT JOIN dbo.Creation_Markets ON Creation_LimitsAndExclusions.CreationID = Creation_Markets.CreationID 
WHERE Creation_LimitsAndExclusions.LeagueCodeID = 37
  AND Creation_Markets.ClassID = 9 and Creation_Markets.IsParentMatch = 1

Answer 2

也不知道关键是什么，但我会在 where 子句中添加一个 cm.creationId IS NOT NULL 条件，以确保我们不会从 Creation_LimitsAndExclusions 中获取不匹配的行

SELECT TOP 200 * 
FROM dbo.Creation_LimitsAndExclusions cle WITH (nolock) 
LEFT JOIN dbo.Creation_Markets cm
    ON cle.CreationID = cm.CreationID 
WHERE cle.LeagueCodeID = 37
    AND cm.ClassID = 9 
    AND cm.IsParentMatch = 1
    AND cm.creationID IS NOT NULL