SQL！= ALL（）难度

Question

对于我正在尝试为Oracle SQL数据库编写的查询，我只是试图从CI表中获取属于某人/某些未列在sys_user中的行的所有行表还没有人工检查下面的查询返回的结果实际上在sys_user表中找到。陌生人stil，owner_id的所有返回值都是相同的。

SELECT 
    ci.sys_id as product_id, 
    ci.name as product, 
    ci.sys_class_name as class_name, 
    ci.owned_by as owner_id 
FROM 
    EDQ_EDW.CMDB_CI CI, 
    EDQ_EDW.CMDB_SYS_USER usr 
WHERE 
    ci.owned_by is not null 
    and ci.owned_by != all(usr.sys_id) 

我已经仔细检查了Oracle文档，以确保我没有正确使用！= ALL（），我不相信我。这是什么造成的？

Answer 1

该ALL,SOME和ANY条件工作的行集，而不是像您在查询中的标量值。尝试这样的事情：

SELECT 
    ci.sys_id as product_id, 
    ci.name as product, 
    ci.sys_class_name as class_name, 
    ci.owned_by as owner_id 
FROM EDQ_EDW.CMDB_CI CI 
WHERE ci.owned_by is not null 
    AND ci.owned_by != ALL (SELECT sys_id FROM EDQ_EDW.CMDB_SYS_USER) 

我不确定逻辑是否正确，虽然语法应该没问题。如果你没有得到你想要的结果，尝试NOT IN来代替：

SELECT 
    ci.sys_id as product_id, 
    ci.name as product, 
    ci.sys_class_name as class_name, 
    ci.owned_by as owner_id 
FROM EDQ_EDW.CMDB_CI CI 
WHERE ci.owned_by is not null 
    AND ci.owned_by NOT IN (SELECT sys_id FROM EDQ_EDW.CMDB_SYS_USER) 

您还可以使用NOT EXISTS或“左联接和检查NULL”查询。这些在某些情况下更快。你可以使用漂亮，简单的例子here找到解释。