[转载] Can anyone interpret this simple SQL?# Database - 数据库
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【 以下文字转载自 Programming 讨论区,原文如下 】
发信人: wellboy (好男孩- MITBBS MEMBER SINCE 1998), 信区: Programming
标 题: Can anyone interpret this simple SQL?
发信站: Unknown Space - 未名空间 (Fri Jan 14 12:13:55 2005) WWW-POST
Access->Queries->New->Find Unmatched Query Wizard->"this wizard creates a
query that finds records in one table that have no related records in another
table"
SELECT A.ID
FROM A LEFT JOIN B ON A.ID = B.ID
WHERE (B.ID Is Null)
What does this SQL mean?
HELP!
发信人: wellboy (好男孩- MITBBS MEMBER SINCE 1998), 信区: Programming
标 题: Can anyone interpret this simple SQL?
发信站: Unknown Space - 未名空间 (Fri Jan 14 12:13:55 2005) WWW-POST
Access->Queries->New->Find Unmatched Query Wizard->"this wizard creates a
query that finds records in one table that have no related records in another
table"
SELECT A.ID
FROM A LEFT JOIN B ON A.ID = B.ID
WHERE (B.ID Is Null)
What does this SQL mean?
HELP!